-------------
       log:  M:\PriorLupia\Submit\Prior Lupia AJPS 08.smcl
  log type:  smcl
 opened on:  10 Jun 2009, 15:40:49

. use "M:\PriorLupia\Submit\Prior Lupia AJPS 08 Rep.dta"

. do "M:\PriorLupia\Submit\Prior Lupia AJPS 08 Rep.do"

. * Replication file for
. * Markus Prior and Arthur Lupia
. * "Money, Time, and Political Learning Skills"
. * American Journal of Political Science
. * Vol. 52, No. 1 (Jan., 2008), pp. 169-83
.
. * Replication files created by Timothy J. Ryan, TJRyan@umich.edu
.
. * This "do" file will applies to the file "Prior Lupia AJPS 08 Rep.dta"
. * The data do not require preparation. Simply load the file into Stata and this
. * program will run in its entirety.
.
. * The file "Prior Lupia AJPS 08 Rep.pdf" contains additional notes about each of
. * the steps below.
.
. *// 1.1 Contextual variables.
.
.         recode group (2 4=1) (1 3=0), gen(time)
(1237 differences between group and time)

.         recode group (3 4=1) (1 2=0), gen(pay)
(1237 differences between group and pay)

.
.
. *// 1.2 Construct demographic/control variables.
.
.         * Interest in politics
.         recode q4 (-2 = .) (-1 4 = 0) (3 = 1) (2 = 2) (1 = 3), gen(polint)
(781 differences between q4 and polint)

.         recode q4 (-2 -1 = .) (4 = 0) (3 = 1) (2 = 2) (1 = 3), gen(polint2)
(781 differences between q4 and polint2)

.
.         * Male = 0; Female = 1
.         recode ppgender (1 = 0) (2 = 1), gen(female)
(1237 differences between ppgender and female)

.
.         * R age
.         recode ppage (0=0), gen(age)
(0 differences between ppage and age)

.
.         * R white?
.         recode ppeth (1=1) (2/4 = 0), gen(white)
(282 differences between ppeth and white)

.
.         * R education
.         recode ppeduc (1 = 1) (2 = 2) (3 = 3) (4 = 4) (5 6 = 6) (7 8 9 = 6), gen(edu)
(185 differences between ppeduc and edu)

.
.         * R income
.         recode ppincimp (1 = 1), gen(income)
(0 differences between ppincimp and income)

.
.         * R married?
.         recode ppmarit (1 = 1) (2/5 = 0), gen(married)
(480 differences between ppmarit and married)

.
.         * R works full time
.         recode ppwork (1/4 = 1) (5/9 = 0), gen(employ)
(633 differences between ppwork and employ)

.
. *// 1.3 Regression variables.
.
.         recode polint (2 = 1) (0 1 3 = 0), gen(intsome)
(1095 differences between polint and intsome)

.         recode polint (3 = 1) (0 1 2 = 0), gen(intmost)
(1095 differences between polint and intmost)

.         recode edu (3 = 1) (1 2 4 5 6 = 0), gen(hsonly)
(1237 differences between edu and hsonly)

.         recode edu (4 = 1) (1 2 3 5 6 = 0), gen(somecol)
(1237 differences between edu and somecol)

.         recode edu (5 6 = 1) (1 2 3 4 = 0), gen(college)
(1237 differences between edu and college)

.         gen age35_44 = 0

.         recode age35_44 (0=1) if age>34 & age<45
(age35_44: 269 changes made)

.         gen age45_59 = 0

.         recode age45_59 (0=1) if age>44 & age<60
(age45_59: 303 changes made)

.         gen age60p = 0

.         recode age60p (0 = 1) if age>59
(age60p: 354 changes made)

.         recode white (0 = 1) (1 = 0), gen(minority)
(1237 differences between white and minority)

.
.
. *// 1.4 Knowledge questions
. * Generate correct/incorrect dummies from question responses. See documentation section 1.4.
.
.         recode q5 (-2/5 = 0) (6=1) (7/999 = 0), gen(q5x)
(1235 differences between q5 and q5x)

.         recode q6 (-2/50 = 0) (51/59 = 1) (60/999 = 0), gen(q6x)
(1236 differences between q6 and q6x)

.         recode q7 (-999/999 = 0), gen(q7x)
(1237 differences between q7 and q7x)

.         recode q7x (0=1) if q7==xanswer
(q7x: 637 changes made)

.         recode q8 (-2 -1 1 3 4 = 0) (2=1), gen(q8x)
(1237 differences between q8 and q8x)

.         recode q9 (-2/3 = 0) (4 = 1) (5 = 0), gen(q9x)
(1237 differences between q9 and q9x)

.         recode q10 (-2/3 = 0) (4 = 1), gen(q10x)
(1237 differences between q10 and q10x)

.         recode q11 (-2/1 = 0) (2 = 1) (3 4 = 0), gen(q11x)
(1237 differences between q11 and q11x)

.         recode q12 (-2/1 = 0) (2 = 1) (3 = 0), gen(q12x)
(1237 differences between q12 and q12x)

.         recode q13 (-2/3 = 0) (4 = 1) (5 = 0), gen(q13x)
(1237 differences between q13 and q13x)

.         recode q14 (-2/4 = 0) (5 = 1), gen(q14x)
(1237 differences between q14 and q14x)

.         recode q15 (-2/9.6 = 0) (9.7/21.6 = 1) (21.7/9999 = 0), gen(q15x)
(1235 differences between q15 and q15x)

.         recode q16 (-2/4 = 0) (5 = 1) (6/7 = 0), gen(q16x)
(1237 differences between q16 and q16x)

.         recode q17 (-2/3 = 0) (4 = 1) (5 = 0), gen(q17x)
(1237 differences between q17 and q17x)

.         recode q18 (-2/6.1 = 0) (6.2/18.5 = 1) (18.6/999 = 0), gen(q18x)
(1235 differences between q18 and q18x)

.
.         label define corrdum 0 "Not correct" 1 "Correct"

.         label values q5x q6x q7x q8x q9x q10x q11x q12x q13x q14x q15x q16x q17x q18x corrdum

.
. * Calculate total number of correct responses
.
.         egen allknow = rsum(q5x q6x q7x q8x q9x q10x q11x q12x q13x q14x q15x q16x q17x q18x)

.
.
.
. *** ANALYSIS
.
. *// 2.1 Remove Rs who did not start knowledge section
.
.         gen nostart=0

.         recode nostart (0=1) if q5==-2
(nostart: 17 changes made)

.         drop if nostart==1
(17 observations deleted)

.
. *// 2.2 Figures for Table 1
.
.         ttest allknow if time==0, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |     312    4.541667    .1571219    2.775327     4.23251    4.850823
60 secon |     306    5.045752    .1688656    2.953941    4.713463    5.378041
---------+--------------------------------------------------------------------
combined |     618    4.791262    .1156062    2.873924    4.564233    5.018291
---------+--------------------------------------------------------------------
    diff |            -.504085    .2305178               -.9567811   -.0513889
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -2.1868
Ho: diff = 0                                     degrees of freedom =      616

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0146         Pr(|T| > |t|) = 0.0291          Pr(T > t) = 0.9854

.         ttest allknow if time==0 & polint==3, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |     106    6.207547    .2622444    2.699972    5.687565    6.727529
60 secon |      99    6.484848    .3023183    3.008029    5.884908    7.084789
---------+--------------------------------------------------------------------
combined |     205    6.341463     .198999    2.849232    5.949105    6.733822
---------+--------------------------------------------------------------------
    diff |           -.2773013    .3987352               -1.063495    .5088924
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -0.6955
Ho: diff = 0                                     degrees of freedom =      203

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.2438         Pr(|T| > |t|) = 0.4876          Pr(T > t) = 0.7562

.         ttest allknow if time==0 & polint==2, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |     108    3.925926    .2456629    2.553003    3.438928    4.412924
60 secon |     114    5.192982    .2677852    2.859164    4.662452    5.723513
---------+--------------------------------------------------------------------
combined |     222    4.576577    .1867027    2.781808    4.208631    4.944522
---------+--------------------------------------------------------------------
    diff |           -1.267057    .3645138               -1.985442   -.5486706
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -3.4760
Ho: diff = 0                                     degrees of freedom =      220

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0003         Pr(|T| > |t|) = 0.0006          Pr(T > t) = 0.9997

.         ttest allknow if time==0 & (polint2==1 | polint2==0), by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |      97    3.453608    .2227506    2.193839    3.011452    3.895765
60 secon |      92    3.315217    .2096167    2.010573     2.89884    3.731595
---------+--------------------------------------------------------------------
combined |     189    3.386243    .1529113    2.102183    3.084601    3.687886
---------+--------------------------------------------------------------------
    diff |            .1383909    .3065796               -.4664081    .7431898
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =   0.4514
Ho: diff = 0                                     degrees of freedom =      187

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.6739         Pr(|T| > |t|) = 0.6522          Pr(T > t) = 0.3261

.         ttest allknow if time==0 & edu>=5, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |      94    6.085106    .3027592    2.935359    5.483887    6.686326
60 secon |      88    6.511364    .3121513    2.928239    5.890929    7.131798
---------+--------------------------------------------------------------------
combined |     182    6.291209    .2173048    2.931601    5.862432    6.719985
---------+--------------------------------------------------------------------
    diff |           -.4262573    .4348931               -1.284402    .4318872
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -0.9801
Ho: diff = 0                                     degrees of freedom =      180

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.1642         Pr(|T| > |t|) = 0.3283          Pr(T > t) = 0.8358

.         ttest allknow if time==0 & edu<=4, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |     218    3.876147    .1640846    2.422681    3.552743     4.19955
60 secon |     218    4.454128    .1867623    2.757513    4.086028    4.822229
---------+--------------------------------------------------------------------
combined |     436    4.165138    .1249298    2.608611    3.919597    4.410679
---------+--------------------------------------------------------------------
    diff |           -.5779817     .248604               -1.066599   -.0893642
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -2.3249
Ho: diff = 0                                     degrees of freedom =      434

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0103         Pr(|T| > |t|) = 0.0205          Pr(T > t) = 0.9897

.         ttest allknow if time==0 & female==1, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |     149    4.127517    .2052036    2.504829    3.722009    4.533024
60 secon |     172    4.482558    .2019007    2.647903    4.084019    4.881097
---------+--------------------------------------------------------------------
combined |     321    4.317757    .1442562    2.584563    4.033947    4.601567
---------+--------------------------------------------------------------------
    diff |           -.3550414    .2890262               -.9236796    .2135969
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -1.2284
Ho: diff = 0                                     degrees of freedom =      319

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.1101         Pr(|T| > |t|) = 0.2202          Pr(T > t) = 0.8899

.         ttest allknow if time==0 & female==0, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |     163    4.920245    .2317294    2.958523    4.462646    5.377845
60 secon |     134    5.768657     .273982    3.171571    5.226731    6.310582
---------+--------------------------------------------------------------------
combined |     297     5.30303    .1787437    3.080413    4.951261      5.6548
---------+--------------------------------------------------------------------
    diff |           -.8484113    .3564053               -1.549831    -.146992
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -2.3805
Ho: diff = 0                                     degrees of freedom =      295

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0090         Pr(|T| > |t|) = 0.0179          Pr(T > t) = 0.9910

.         ttest allknow if time==0 & age<35, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |      72    4.555556    .3255481    2.762367    3.906431     5.20468
60 secon |      78    4.384615     .333615    2.946408    3.720303    5.048928
---------+--------------------------------------------------------------------
combined |     150    4.466667    .2328054    2.851272     4.00664    4.926693
---------+--------------------------------------------------------------------
    diff |            .1709402    .4673442               -.7525892     1.09447
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =   0.3658
Ho: diff = 0                                     degrees of freedom =      148

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.6425         Pr(|T| > |t|) = 0.7151          Pr(T > t) = 0.3575

.         ttest allknow if time==0 & age>34 & age <60, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |     144    4.479167    .2381555    2.857865    4.008407    4.949927
60 secon |     147    5.360544    .2494884    3.024887    4.867469     5.85362
---------+--------------------------------------------------------------------
combined |     291    4.924399    .1741819    2.971321    4.581578     5.26722
---------+--------------------------------------------------------------------
    diff |           -.8813776    .3451119               -1.560629    -.202126
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -2.5539
Ho: diff = 0                                     degrees of freedom =      289

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0056         Pr(|T| > |t|) = 0.0112          Pr(T > t) = 0.9944

.         ttest allknow if time==0 & age>59, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |      96       4.625    .2739614    2.684262    4.081118    5.168882
60 secon |      81    5.111111    .3063122     2.75681     4.50153    5.720692
---------+--------------------------------------------------------------------
combined |     177    4.847458    .2045076    2.720797    4.443855     5.25106
---------+--------------------------------------------------------------------
    diff |           -.4861111    .4100197               -1.295331    .3231089
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -1.1856
Ho: diff = 0                                     degrees of freedom =      175

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.1187         Pr(|T| > |t|) = 0.2374          Pr(T > t) = 0.8813

.         ttest allknow if time==0 & white==1, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |     241    4.742739    .1759213    2.731033    4.396192    5.089286
60 secon |     236    5.550847    .1919959    2.949497    5.172594      5.9291
---------+--------------------------------------------------------------------
combined |     477    5.142558    .1312665    2.866903    4.884624    5.400491
---------+--------------------------------------------------------------------
    diff |           -.8081089    .2601949               -1.319384   -.2968335
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -3.1058
Ho: diff = 0                                     degrees of freedom =      475

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0010         Pr(|T| > |t|) = 0.0020          Pr(T > t) = 0.9990

.         ttest allknow if time==0 & white==0, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |      71    3.859155    .3364484    2.834964     3.18813     4.53018
60 secon |      70    3.342857    .2706374    2.264315     2.80295    3.882764
---------+--------------------------------------------------------------------
combined |     141    3.602837    .2165586     2.57149    3.174689    4.030985
---------+--------------------------------------------------------------------
    diff |            .5162978    .4324717               -.3387757    1.371371
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =   1.1938
Ho: diff = 0                                     degrees of freedom =      139

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.8827         Pr(|T| > |t|) = 0.2346          Pr(T > t) = 0.1173

.         ttest allknow if time==0 & employ==1, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |     173    4.543353    .2239916    2.946149    4.101226    4.985479
60 secon |     168    5.053571    .2358422    3.056864    4.587955    5.519188
---------+--------------------------------------------------------------------
combined |     341    4.794721    .1628735    3.007652    4.474355    5.115088
---------+--------------------------------------------------------------------
    diff |           -.5102188    .3250832               -1.149653    .1292154
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -1.5695
Ho: diff = 0                                     degrees of freedom =      339

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0587         Pr(|T| > |t|) = 0.1175          Pr(T > t) = 0.9413

.         ttest allknow if time==0 & employ==0, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |     139    4.539568    .2169124     2.55736    4.110667     4.96847
60 secon |     138    5.036232    .2413004    2.834638    4.559077    5.513387
---------+--------------------------------------------------------------------
combined |     277    4.787004    .1625653    2.705626    4.466978    5.107029
---------+--------------------------------------------------------------------
    diff |           -.4966635    .3243435               -1.135175     .141848
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -1.5313
Ho: diff = 0                                     degrees of freedom =      275

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0634         Pr(|T| > |t|) = 0.1268          Pr(T > t) = 0.9366

.         ttest allknow if time==0 & married==1, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |     185    4.827027    .2045649    2.782383    4.423433    5.230621
60 secon |     186    5.252688    .2106662    2.873103    4.837071    5.668305
---------+--------------------------------------------------------------------
combined |     371    5.040431    .1470527    2.832435    4.751267    5.329595
---------+--------------------------------------------------------------------
    diff |           -.4256611    .2936698               -1.003138    .1518152
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -1.4495
Ho: diff = 0                                     degrees of freedom =      369

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0740         Pr(|T| > |t|) = 0.1481          Pr(T > t) = 0.9260

.         ttest allknow if time==0 & married==0, by(group)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
60 secon |     127    4.125984    .2415921    2.722604    3.647881    4.604088
60 secon |     120       4.725    .2792955    3.059528    4.171967    5.278033
---------+--------------------------------------------------------------------
combined |     247    4.417004    .1845756    2.900833    4.053454    4.780554
---------+--------------------------------------------------------------------
    diff |           -.5990157    .3680682               -1.323997     .125966
---------+--------------------------------------------------------------------
    diff = mean(60 secon) - mean(60 secon)                        t =  -1.6275
Ho: diff = 0                                     degrees of freedom =      245

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0525         Pr(|T| > |t|) = 0.1049          Pr(T > t) = 0.9475

.
. *// 2.3 Figures for Table 3
.
.         ttest allknow if pay==0, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |     312    4.541667    .1571219    2.775327     4.23251    4.850823
       1 |     302    5.350993    .1688223    2.933819    5.018772    5.683215
---------+--------------------------------------------------------------------
combined |     614    4.939739    .1162537    2.880652    4.711436    5.168043
---------+--------------------------------------------------------------------
    diff |           -.8093267    .2304172               -1.261831   -.3568224
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -3.5124
Ho: diff = 0                                     degrees of freedom =      612

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0002         Pr(|T| > |t|) = 0.0005          Pr(T > t) = 0.9998

.         ttest allknow if pay==0 & polint==3, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |     106    6.207547    .2622444    2.699972    5.687565    6.727529
       1 |     109    6.275229    .2733712    2.854079     5.73336    6.817099
---------+--------------------------------------------------------------------
combined |     215     6.24186    .1891092    2.772885    5.869105    6.614616
---------+--------------------------------------------------------------------
    diff |           -.0676822    .3791138               -.8149776    .6796132
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -0.1785
Ho: diff = 0                                     degrees of freedom =      213

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.4292         Pr(|T| > |t|) = 0.8585          Pr(T > t) = 0.5708

.         ttest allknow if pay==0 & polint==2, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |     108    3.925926    .2456629    2.553003    3.438928    4.412924
       1 |     113    5.283186    .2775494     2.95039    4.733257    5.833114
---------+--------------------------------------------------------------------
combined |     221     4.61991    .1910197    2.839712    4.243447    4.996372
---------+--------------------------------------------------------------------
    diff |            -1.35726    .3718656               -2.090153   -.6243666
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -3.6499
Ho: diff = 0                                     degrees of freedom =      219

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0002         Pr(|T| > |t|) = 0.0003          Pr(T > t) = 0.9998

.         ttest allknow if pay==0 & (polint2==1 | polint2==0), by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |      97    3.453608    .2227506    2.193839    3.011452    3.895765
       1 |      79    4.151899    .2922168     2.59728     3.57014    4.733658
---------+--------------------------------------------------------------------
combined |     176    3.767045    .1810368    2.401724    3.409749    4.124342
---------+--------------------------------------------------------------------
    diff |           -.6982905    .3611676               -1.411124    .0145429
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -1.9334
Ho: diff = 0                                     degrees of freedom =      174

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0274         Pr(|T| > |t|) = 0.0548          Pr(T > t) = 0.9726

.         ttest allknow if pay==0 & edu>=5, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |      94    6.085106    .3027592    2.935359    5.483887    6.686326
       1 |      96       6.375    .3245273    3.179705    5.730732    7.019268
---------+--------------------------------------------------------------------
combined |     190    6.231579    .2217504    3.056618    5.794155    6.669003
---------+--------------------------------------------------------------------
    diff |           -.2898936    .4442005               -1.166151     .586364
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -0.6526
Ho: diff = 0                                     degrees of freedom =      188

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.2574         Pr(|T| > |t|) = 0.5148          Pr(T > t) = 0.7426

.         ttest allknow if pay==0 & edu<=4, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |     218    3.876147    .1640846    2.422681    3.552743     4.19955
       1 |     206    4.873786    .1873781    2.689382    4.504351    5.243222
---------+--------------------------------------------------------------------
combined |     424    4.360849    .1263182     2.60105     4.11256    4.609139
---------+--------------------------------------------------------------------
    diff |           -.9976396    .2483327               -1.485763   -.5095165
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -4.0174
Ho: diff = 0                                     degrees of freedom =      422

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0000         Pr(|T| > |t|) = 0.0001          Pr(T > t) = 1.0000

.         ttest allknow if pay==0 & female==1, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |     149    4.127517    .2052036    2.504829    3.722009    4.533024
       1 |     166    5.048193    .2241054    2.887396    4.605709    5.490677
---------+--------------------------------------------------------------------
combined |     315    4.612698    .1548184    2.747755    4.308086    4.917311
---------+--------------------------------------------------------------------
    diff |            -.920676     .306193               -1.523133   -.3182193
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -3.0068
Ho: diff = 0                                     degrees of freedom =      313

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0014         Pr(|T| > |t|) = 0.0029          Pr(T > t) = 0.9986

.         ttest allknow if pay==0 & female==0, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |     163    4.920245    .2317294    2.958523    4.462646    5.377845
       1 |     136    5.720588     .253664    2.958206    5.218919    6.222258
---------+--------------------------------------------------------------------
combined |     299    5.284281    .1723534    2.980269    4.945097    5.623465
---------+--------------------------------------------------------------------
    diff |           -.8003428    .3435786                 -1.4765   -.1241858
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -2.3294
Ho: diff = 0                                     degrees of freedom =      297

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0103         Pr(|T| > |t|) = 0.0205          Pr(T > t) = 0.9897

.         ttest allknow if pay==0 & age<35, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |      72    4.555556    .3255481    2.762367    3.906431     5.20468
       1 |      74    4.405405    .3242163    2.789014    3.759243    5.051568
---------+--------------------------------------------------------------------
combined |     146    4.479452    .2290271    2.767344    4.026789    4.932115
---------+--------------------------------------------------------------------
    diff |            .1501502    .4595146                -.758115    1.058415
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =   0.3268
Ho: diff = 0                                     degrees of freedom =      144

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.6278         Pr(|T| > |t|) = 0.7443          Pr(T > t) = 0.3722

.         ttest allknow if pay==0 & age>34 & age<60, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |     144    4.479167    .2381555    2.857865    4.008407    4.949927
       1 |     137    5.255474    .2527286    2.958112    4.755688    5.755261
---------+--------------------------------------------------------------------
combined |     281    4.857651    .1746631    2.927887    4.513832    5.201471
---------+--------------------------------------------------------------------
    diff |           -.7763078    .3469613               -1.459302   -.0933134
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -2.2374
Ho: diff = 0                                     degrees of freedom =      279

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0130         Pr(|T| > |t|) = 0.0260          Pr(T > t) = 0.9870

.         ttest allknow if pay==0 & age>=60, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |      96       4.625    .2739614    2.684262    4.081118    5.168882
       1 |      91    6.263736    .2901876    2.768213    5.687228    6.840245
---------+--------------------------------------------------------------------
combined |     187     5.42246    .2076415    2.839455    5.012825    5.832095
---------+--------------------------------------------------------------------
    diff |           -1.638736    .3987484               -2.425415   -.8520576
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -4.1097
Ho: diff = 0                                     degrees of freedom =      185

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0000         Pr(|T| > |t|) = 0.0001          Pr(T > t) = 1.0000

.         ttest allknow if pay==0 & white==1, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |     241    4.742739    .1759213    2.731033    4.396192    5.089286
       1 |     225    5.742222    .1956394    2.934591    5.356693    6.127751
---------+--------------------------------------------------------------------
combined |     466    5.225322    .1330401    2.871941    4.963888    5.486756
---------+--------------------------------------------------------------------
    diff |           -.9994836    .2624539               -1.515229   -.4837381
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -3.8082
Ho: diff = 0                                     degrees of freedom =      464

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0001         Pr(|T| > |t|) = 0.0002          Pr(T > t) = 0.9999

.         ttest allknow if pay==0 & white==0, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |      71    3.859155    .3364484    2.834964     3.18813     4.53018
       1 |      77    4.207792    .2999987    2.632478    3.610293    4.805291
---------+--------------------------------------------------------------------
combined |     148    4.040541    .2242182    2.727732    3.597433    4.483648
---------+--------------------------------------------------------------------
    diff |           -.3486373    .4494145               -1.236836     .539561
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -0.7758
Ho: diff = 0                                     degrees of freedom =      146

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.2196         Pr(|T| > |t|) = 0.4391          Pr(T > t) = 0.7804

.         ttest allknow if pay==0 & employ==1, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |     173    4.543353    .2239916    2.946149    4.101226    4.985479
       1 |     172    5.261628    .2266744    2.972807    4.814188    5.709068
---------+--------------------------------------------------------------------
combined |     345    4.901449    .1602747     2.97697    4.586208    5.216691
---------+--------------------------------------------------------------------
    diff |           -.7182753    .3186663               -1.345061   -.0914892
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -2.2540
Ho: diff = 0                                     degrees of freedom =      343

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0124         Pr(|T| > |t|) = 0.0248          Pr(T > t) = 0.9876

.         ttest allknow if pay==0 & employ==0, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |     139    4.539568    .2169124     2.55736    4.110667     4.96847
       1 |     130    5.469231    .2533469      2.8886    4.967978    5.970484
---------+--------------------------------------------------------------------
combined |     269    4.988848    .1680925    2.756922    4.657898    5.319797
---------+--------------------------------------------------------------------
    diff |           -.9296624    .3321654               -1.583659   -.2756658
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -2.7988
Ho: diff = 0                                     degrees of freedom =      267

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0028         Pr(|T| > |t|) = 0.0055          Pr(T > t) = 0.9972

.         ttest allknow if pay==0 & married==1, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |     185    4.827027    .2045649    2.782383    4.423433    5.230621
       1 |     185     5.72973    .2153405    2.928947    5.304876    6.154584
---------+--------------------------------------------------------------------
combined |     370    5.278378    .1501562    2.888313    4.983109    5.573648
---------+--------------------------------------------------------------------
    diff |           -.9027027    .2970157               -1.486764   -.3186418
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -3.0392
Ho: diff = 0                                     degrees of freedom =      368

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0013         Pr(|T| > |t|) = 0.0025          Pr(T > t) = 0.9987

.         ttest allknow if pay==0 & married==0, by(time)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       0 |     127    4.125984    .2415921    2.722604    3.647881    4.604088
       1 |     117    4.752137    .2637065    2.852422    4.229833    5.274441
---------+--------------------------------------------------------------------
combined |     244     4.42623    .1790894    2.797465    4.073464    4.778995
---------+--------------------------------------------------------------------
    diff |           -.6261525    .3569576               -1.329293     .076988
---------+--------------------------------------------------------------------
    diff = mean(0) - mean(1)                                      t =  -1.7541
Ho: diff = 0                                     degrees of freedom =      242

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0403         Pr(|T| > |t|) = 0.0807          Pr(T > t) = 0.9597

.
.         recode group (1=1) (2=.) (3=.) (4=4), gen(CvsTxM)
(608 differences between group and CvsTxM)

.
.         ttest allknow, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |     312    4.541667    .1571219    2.775327     4.23251    4.850823
       4 |     300    5.633333    .1788626    3.097991    5.281344    5.985322
---------+--------------------------------------------------------------------
combined |     612    5.076797    .1206974    2.985889    4.839765    5.313829
---------+--------------------------------------------------------------------
    diff |           -1.091667    .2375621               -1.558206   -.6251278
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -4.5953
Ho: diff = 0                                     degrees of freedom =      610

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0000         Pr(|T| > |t|) = 0.0000          Pr(T > t) = 1.0000

.         ttest allknow if polint==3, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |     106    6.207547    .2622444    2.699972    5.687565    6.727529
       4 |      99    6.808081    .3393631    3.376621    6.134626    7.481536
---------+--------------------------------------------------------------------
combined |     205    6.497561    .2132198    3.052842    6.077164    6.917958
---------+--------------------------------------------------------------------
    diff |           -.6005336    .4256563               -1.439808    .2387409
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -1.4108
Ho: diff = 0                                     degrees of freedom =      203

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0799         Pr(|T| > |t|) = 0.1598          Pr(T > t) = 0.9201

.         ttest allknow if polint==2, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |     108    3.925926    .2456629    2.553003    3.438928    4.412924
       4 |     119    5.394958    .2645074    2.885435    4.871161    5.918755
---------+--------------------------------------------------------------------
combined |     227    4.696035    .1874189    2.823751    4.326723    5.065347
---------+--------------------------------------------------------------------
    diff |           -1.469032    .3631373               -2.184617    -.753447
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -4.0454
Ho: diff = 0                                     degrees of freedom =      225

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0000         Pr(|T| > |t|) = 0.0001          Pr(T > t) = 1.0000

.         ttest allknow if (polint2==1 | polint2==0), by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |      97    3.453608    .2227506    2.193839    3.011452    3.895765
       4 |      80      4.5875    .2894198     2.58865    4.011424    5.163576
---------+--------------------------------------------------------------------
combined |     177    3.966102    .1833984    2.439957    3.604159    4.328045
---------+--------------------------------------------------------------------
    diff |           -1.133892     .359474               -1.843354   -.4244294
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -3.1543
Ho: diff = 0                                     degrees of freedom =      175

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0009         Pr(|T| > |t|) = 0.0019          Pr(T > t) = 0.9991

.         ttest allknow if edu>=5, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |      94    6.085106    .3027592    2.935359    5.483887    6.686326
       4 |      86    6.744186    .3699322     3.43061    6.008662     7.47971
---------+--------------------------------------------------------------------
combined |     180         6.4    .2377476    3.189718    5.930851    6.869149
---------+--------------------------------------------------------------------
    diff |           -.6590797    .4747372               -1.595917    .2777577
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -1.3883
Ho: diff = 0                                     degrees of freedom =      178

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0834         Pr(|T| > |t|) = 0.1668          Pr(T > t) = 0.9166

.         ttest allknow if edu<=4, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |     218    3.876147    .1640846    2.422681    3.552743     4.19955
       4 |     214    5.186916    .1942825    2.842107    4.803953    5.569878
---------+--------------------------------------------------------------------
combined |     432    4.525463    .1306814    2.716163    4.268611    4.782315
---------+--------------------------------------------------------------------
    diff |           -1.310769    .2539285               -1.809865   -.8116736
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -5.1620
Ho: diff = 0                                     degrees of freedom =      430

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0000         Pr(|T| > |t|) = 0.0000          Pr(T > t) = 1.0000

.         ttest allknow if female==1, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |     149    4.127517    .2052036    2.504829    3.722009    4.533024
       4 |     142    5.330986    .2563199    3.054405    4.824259    5.837713
---------+--------------------------------------------------------------------
combined |     291    4.714777      .16685    2.846248    4.386386    5.043167
---------+--------------------------------------------------------------------
    diff |           -1.203469    .3267937               -1.846667   -.5602716
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -3.6827
Ho: diff = 0                                     degrees of freedom =      289

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0001         Pr(|T| > |t|) = 0.0003          Pr(T > t) = 0.9999

.         ttest allknow if female==0, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |     163    4.920245    .2317294    2.958523    4.462646    5.377845
       4 |     158    5.905063    .2483174    3.121301    5.414589    6.395537
---------+--------------------------------------------------------------------
combined |     321    5.404984    .1716171    3.074772    5.067344    5.742625
---------+--------------------------------------------------------------------
    diff |           -.9848179    .3393631                -1.65249   -.3171453
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -2.9020
Ho: diff = 0                                     degrees of freedom =      319

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0020         Pr(|T| > |t|) = 0.0040          Pr(T > t) = 0.9980

.         ttest allknow if age<35, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |      72    4.555556    .3255481    2.762367    3.906431     5.20468
       4 |      84     4.97619    .3408404    3.123854    4.298273    5.654108
---------+--------------------------------------------------------------------
combined |     156    4.782051    .2370369     2.96059    4.313812    5.250291
---------+--------------------------------------------------------------------
    diff |           -.4206349    .4758182               -1.360608    .5193383
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -0.8840
Ho: diff = 0                                     degrees of freedom =      154

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.1890         Pr(|T| > |t|) = 0.3781          Pr(T > t) = 0.8110

.         ttest allknow if age>34 & age<60, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |     144    4.479167    .2381555    2.857865    4.008407    4.949927
       4 |     139    5.906475    .2599078    3.064268    5.392558    6.420392
---------+--------------------------------------------------------------------
combined |     283    5.180212    .1807674    3.040979    4.824387    5.536037
---------+--------------------------------------------------------------------
    diff |           -1.427308    .3520848               -2.120367   -.7342497
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -4.0539
Ho: diff = 0                                     degrees of freedom =      281

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0000         Pr(|T| > |t|) = 0.0001          Pr(T > t) = 1.0000

.         ttest allknow if age>=60, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |      96       4.625    .2739614    2.684262    4.081118    5.168882
       4 |      77    5.857143    .3491589    3.063857    5.161733    6.552553
---------+--------------------------------------------------------------------
combined |     173     5.17341      .22172    2.916271    4.735768    5.611053
---------+--------------------------------------------------------------------
    diff |           -1.232143    .4374078               -2.095557   -.3687288
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -2.8169
Ho: diff = 0                                     degrees of freedom =      171

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0027         Pr(|T| > |t|) = 0.0054          Pr(T > t) = 0.9973

.         ttest allknow if white==1, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |     241    4.742739    .1759213    2.731033    4.396192    5.089286
       4 |     239    6.008368    .1987967    3.073322    5.616742    6.399994
---------+--------------------------------------------------------------------
combined |     480    5.372917    .1356421     2.97177     5.10639    5.639444
---------+--------------------------------------------------------------------
    diff |            -1.26563    .2653286               -1.786984   -.7442749
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -4.7700
Ho: diff = 0                                     degrees of freedom =      478

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0000         Pr(|T| > |t|) = 0.0000          Pr(T > t) = 1.0000

.         ttest allknow if white==0, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |      71    3.859155    .3364484    2.834964     3.18813     4.53018
       4 |      61    4.163934    .3531129      2.7579    3.457604    4.870265
---------+--------------------------------------------------------------------
combined |     132           4      .24311    2.793121     3.51907     4.48093
---------+--------------------------------------------------------------------
    diff |           -.3047795    .4887628               -1.271738    .6621792
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -0.6236
Ho: diff = 0                                     degrees of freedom =      130

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.2670         Pr(|T| > |t|) = 0.5340          Pr(T > t) = 0.7330

.         ttest allknow if employ==1, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |     173    4.543353    .2239916    2.946149    4.101226    4.985479
       4 |     170    5.647059    .2373733     3.09497     5.17846    6.115658
---------+--------------------------------------------------------------------
combined |     343    5.090379    .1655813    3.066609    4.764693    5.416065
---------+--------------------------------------------------------------------
    diff |           -1.103706    .3262305               -1.745384   -.4620287
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -3.3832
Ho: diff = 0                                     degrees of freedom =      341

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0004         Pr(|T| > |t|) = 0.0008          Pr(T > t) = 0.9996

.         ttest allknow if employ==0, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |     139    4.539568    .2169124     2.55736    4.110667     4.96847
       4 |     130    5.615385    .2731002    3.113822    5.075049     6.15572
---------+--------------------------------------------------------------------
combined |     269     5.05948    .1759183    2.885274    4.713122    5.405837
---------+--------------------------------------------------------------------
    diff |           -1.075816    .3464925               -1.758021   -.3936111
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -3.1049
Ho: diff = 0                                     degrees of freedom =      267

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0011         Pr(|T| > |t|) = 0.0021          Pr(T > t) = 0.9989

.         ttest allknow if married==1, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |     185    4.827027    .2045649    2.782383    4.423433    5.230621
       4 |     191    6.005236    .2227731    3.078785    5.565809    6.444662
---------+--------------------------------------------------------------------
combined |     376    5.425532    .1542751    2.991506    5.122179    5.728885
---------+--------------------------------------------------------------------
    diff |           -1.178209    .3029363               -1.773881   -.5825366
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -3.8893
Ho: diff = 0                                     degrees of freedom =      374

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0001         Pr(|T| > |t|) = 0.0001          Pr(T > t) = 0.9999

.         ttest allknow if married==0, by(CvsTxM)

Two-sample t test with equal variances
---------+--------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
       1 |     127    4.125984    .2415921    2.722604    3.647881    4.604088
       4 |     109    4.981651    .2908684    3.036755      4.4051    5.558203
---------+--------------------------------------------------------------------
combined |     236    4.521186    .1886088    2.897463    4.149606    4.892767
---------+--------------------------------------------------------------------
    diff |           -.8556671    .3749779               -1.594431    -.116903
---------+--------------------------------------------------------------------
    diff = mean(1) - mean(4)                                      t =  -2.2819
Ho: diff = 0                                     degrees of freedom =      234

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(T < t) = 0.0117         Pr(|T| > |t|) = 0.0234          Pr(T > t) = 0.9883

.
. *// 2.4 Figures for Table 4. (Also table 2, which is a subset of Table 4.)
.
.         bysort group: regress allknow intsome intmost hsonly somecol college female age35_44 age45_59 age60p minority income employ married

-------------
-> group = 60 second

      Source |       SS       df       MS              Number of obs =     312
-------------+------------------------------           F( 13,   298) =   13.06
       Model |  869.443025    13  66.8802327           Prob > F      =  0.0000
    Residual |  1526.01531   298  5.12085674           R-squared     =  0.3630
-------------+------------------------------           Adj R-squared =  0.3352
       Total |  2395.45833   311  7.70243837           Root MSE      =  2.2629

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
     intsome |   .0339096    .339204     0.10   0.920    -.6336292    .7014483
     intmost |   1.937805   .3615384     5.36   0.000     1.226313    2.649297
      hsonly |   .2521308   .3852333     0.65   0.513    -.5059915    1.010253
     somecol |   .5057705     .45839     1.10   0.271    -.3963212    1.407862
     college |   1.829173   .4213169     4.34   0.000     1.000039    2.658306
      female |  -.3757411   .2648778    -1.42   0.157    -.8970092    .1455269
    age35_44 |  -.2903481   .3848617    -0.75   0.451    -1.047739    .4670429
    age45_59 |    -.22744   .3887531    -0.59   0.559    -.9924891    .5376091
      age60p |  -.6343792   .4212066    -1.51   0.133    -1.463295     .194537
    minority |   -.840479   .3358872    -2.50   0.013     -1.50149   -.1794677
      income |   .1830259   .0363469     5.04   0.000     .1114967    .2545551
      employ |  -.7274535    .322263    -2.26   0.025    -1.361653   -.0932539
     married |    -.07903   .2820802    -0.28   0.780    -.6341516    .4760915
       _cons |   2.468748    .563742     4.38   0.000     1.359328    3.578168
-------------+----------------------------------------------------------------

-------------
-> group = 24 hours/

      Source |       SS       df       MS              Number of obs =     302
-------------+------------------------------           F( 13,   288) =    6.77
       Model |  606.516592    13  46.6551225           Prob > F      =  0.0000
    Residual |  1984.27811   288  6.88985455           R-squared     =  0.2341
-------------+------------------------------           Adj R-squared =  0.1995
       Total |   2590.7947   301  8.60729137           Root MSE      =  2.6249

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
     intsome |   .8593088   .3986737     2.16   0.032     .0746252    1.643992
     intmost |   1.262355   .4222476     2.99   0.003     .4312729    2.093438
      hsonly |   .5246996   .4670435     1.12   0.262    -.3945518    1.443951
     somecol |    .761148   .5012396     1.52   0.130    -.2254094    1.747705
     college |   1.800817   .4828894     3.73   0.000     .8503775    2.751257
      female |  -.4721687   .3187145    -1.48   0.140    -1.099474    .1551365
    age35_44 |   .2629658   .4652746     0.57   0.572     -.652804    1.178736
    age45_59 |   .5451943   .4595343     1.19   0.236    -.3592773    1.449666
      age60p |   1.551538   .5037758     3.08   0.002      .559989    2.543088
    minority |  -1.081189   .3708891    -2.92   0.004    -1.811186   -.3511919
      income |   .1055315   .0445065     2.37   0.018     .0179322    .1931309
      employ |   .0427641   .3826446     0.11   0.911    -.7103704    .7958986
     married |   .3256223   .3319972     0.98   0.328    -.3278263    .9790709
       _cons |   2.258103   .7508538     3.01   0.003     .7802463     3.73596
-------------+----------------------------------------------------------------

-------------
-> group = 60 second

      Source |       SS       df       MS              Number of obs =     306
-------------+------------------------------           F( 13,   292) =   14.08
       Model |  1025.47206    13  78.8824664           Prob > F      =  0.0000
    Residual |  1635.88741   292  5.60235416           R-squared     =  0.3853
-------------+------------------------------           Adj R-squared =  0.3580
       Total |  2661.35948   305  8.72576878           Root MSE      =  2.3669

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
     intsome |    1.50439    .359816     4.18   0.000     .7962289    2.212552
     intmost |   2.255726   .3911833     5.77   0.000     1.485829    3.025622
      hsonly |   .5925634   .4300703     1.38   0.169    -.2538671    1.438994
     somecol |   .8922819   .4524858     1.97   0.050     .0017348    1.782829
     college |   1.733116   .4621316     3.75   0.000     .8235848    2.642647
      female |  -.8908938    .276547    -3.22   0.001    -1.435172   -.3466157
    age35_44 |  -.3709089   .4110128    -0.90   0.368    -1.179832    .4380141
    age45_59 |   .3796165   .4138573     0.92   0.360    -.4349049    1.194138
      age60p |  -.3287099   .4408261    -0.75   0.456    -1.196309    .5388894
    minority |  -1.813491   .3449791    -5.26   0.000    -2.492452    -1.13453
      income |   .1177389   .0361056     3.26   0.001     .0466788     .188799
      employ |  -.5717208   .3123626    -1.83   0.068    -1.186488    .0430467
     married |  -.0124349   .2946526    -0.04   0.966    -.5923471    .5674773
       _cons |   3.016299   .5928575     5.09   0.000     1.849483    4.183114
-------------+----------------------------------------------------------------

-------------
-> group = 24 hours/

      Source |       SS       df       MS              Number of obs =     300
-------------+------------------------------           F( 13,   286) =    7.87
       Model |  755.955767    13  58.1504436           Prob > F      =  0.0000
    Residual |   2113.7109   286  7.39059755           R-squared     =  0.2634
-------------+------------------------------           Adj R-squared =  0.2299
       Total |  2869.66667   299  9.59754738           Root MSE      =  2.7186

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
     intsome |   -.008958   .4145855    -0.02   0.983    -.8249839    .8070679
     intmost |   1.081061   .4473127     2.42   0.016     .2006185    1.961504
      hsonly |   .4292544   .5034524     0.85   0.395    -.5616875    1.420196
     somecol |   2.393365   .5683315     4.21   0.000     1.274722    3.512009
     college |    2.19765   .5688462     3.86   0.000     1.077993    3.317306
      female |  -.3163322   .3244049    -0.98   0.330    -.9548561    .3221918
    age35_44 |   .4359785   .4697363     0.93   0.354    -.4886003    1.360557
    age45_59 |   .6275844   .4567457     1.37   0.171    -.2714251    1.526594
      age60p |   1.048962   .4989566     2.10   0.036     .0668694    2.031055
    minority |  -1.922871   .4099848    -4.69   0.000    -2.729841     -1.1159
      income |   .1154466   .0471155     2.45   0.015     .0227094    .2081838
      employ |  -.1488175   .3810211    -0.39   0.696    -.8987789    .6011438
     married |   .1628155   .3584792     0.45   0.650    -.5427766    .8684077
       _cons |   2.814731   .6996507     4.02   0.000     1.437613    4.191848
-------------+----------------------------------------------------------------


.
.
. *// 2.5
.
.
. *2.5.1 Principal-components analysis
. *Published results (see documentation)
.
.         gen q15alt = q15x

.         recode q15alt (0 = .) if q15==-2
(q15alt: 19 changes made)

.
.         gen q18alt = q18x

.         recode q18alt (0=.) if q18==-2
(q18alt: 24 changes made)

.
.         bysort group: factor q5x q6x q7x q8x q9x q10x q11x q12x q13x q14x q15alt q16x q17x q18alt, pcf

-------------
-> group = 60 second
(obs=310)

Factor analysis/correlation                        Number of obs    =      310
    Method: principal-component factors            Retained factors =        5
    Rotation: (unrotated)                          Number of params =       60

    -------------+------------------------------------------------------------
         Factor  | Eigenvalue     Difference        Proportion   Cumulative
    -------------+------------------------------------------------------------
    Factor1    |      2.87552      1.52621            0.2054       0.2054
    Factor2    |      1.34930      0.18408            0.0964       0.3018
    Factor3    |      1.16523      0.10198            0.0832       0.3850
    Factor4    |      1.06325      0.03236            0.0759       0.4609
    Factor5    |      1.03089      0.13733            0.0736       0.5346
    Factor6    |      0.89356      0.04269            0.0638       0.5984
    Factor7    |      0.85087      0.02040            0.0608       0.6592
    Factor8    |      0.83048      0.04737            0.0593       0.7185
    Factor9    |      0.78310      0.01697            0.0559       0.7744
    Factor10    |      0.76613      0.05948            0.0547       0.8292
    Factor11    |      0.70665      0.09936            0.0505       0.8796
    Factor12    |      0.60729      0.05914            0.0434       0.9230
    Factor13    |      0.54815      0.01858            0.0392       0.9622
    Factor14    |      0.52957            .            0.0378       1.0000
    -------------+------------------------------------------------------------
    LR test: independent vs. saturated:  chi2(91) =  442.45 Prob>chi2 = 0.0000

Factor loadings (pattern matrix) and unique variances

    -------------+--------------------------------------------------+--------------
    Variable   | Factor1    Factor2    Factor3    Factor4    Factor5   | Uniqueness
    -------------+--------------------------------------------------+--------------
    q5x   |   0.5511      0.0697      0.0762      0.3486      0.1281   |     0.5476
    q6x   |   0.5276     -0.0019     -0.1902      0.2705     -0.5630   |     0.2953
    q7x   |   0.3662      0.4724      0.0661     -0.2645      0.2381   |     0.5118
    q8x   |   0.0279      0.3803      0.6347      0.4756      0.1375   |     0.2067
    q9x   |   0.4618      0.3583     -0.0797     -0.2310      0.1299   |     0.5817
    q10x   |   0.4855      0.3443     -0.1904     -0.0684     -0.0522   |     0.6021
    q11x   |   0.3140     -0.4652     -0.2882     -0.1275      0.4651   |     0.3693
    q12x   |   0.5558     -0.1721     -0.2125      0.0831      0.1395   |     0.5900
    q13x   |   0.5412     -0.1760      0.0219      0.2111      0.1032   |     0.6205
    q14x   |   0.2682      0.3576      0.0875     -0.5367     -0.1788   |     0.4726
    q15alt   |   0.5216     -0.2753      0.5234     -0.1613      0.0220   |     0.3517
    q16x   |   0.2004      0.3728     -0.4234      0.3348      0.2725   |     0.4552
    q17x   |   0.5229     -0.1118     -0.0685      0.0247     -0.4891   |     0.4695
    q18alt   |   0.5929     -0.3125      0.2814     -0.1412      0.0995   |     0.4418
    -------------+--------------------------------------------------+--------------

-------------
-> group = 24 hours/
(obs=291)

Factor analysis/correlation                        Number of obs    =      291
    Method: principal-component factors            Retained factors =        5
    Rotation: (unrotated)                          Number of params =       60

    -------------+------------------------------------------------------------
         Factor  | Eigenvalue     Difference        Proportion   Cumulative
    -------------+------------------------------------------------------------
    Factor1    |      2.91770      1.62567            0.2084       0.2084
    Factor2    |      1.29203      0.11729            0.0923       0.3007
    Factor3    |      1.17474      0.11884            0.0839       0.3846
    Factor4    |      1.05590      0.04304            0.0754       0.4600
    Factor5    |      1.01286      0.10645            0.0723       0.5324
    Factor6    |      0.90641      0.03550            0.0647       0.5971
    Factor7    |      0.87091      0.06159            0.0622       0.6593
    Factor8    |      0.80932      0.02630            0.0578       0.7171
    Factor9    |      0.78302      0.01998            0.0559       0.7731
    Factor10    |      0.76305      0.08382            0.0545       0.8276
    Factor11    |      0.67923      0.03989            0.0485       0.8761
    Factor12    |      0.63935      0.03907            0.0457       0.9218
    Factor13    |      0.60028      0.10508            0.0429       0.9646
    Factor14    |      0.49520            .            0.0354       1.0000
    -------------+------------------------------------------------------------
    LR test: independent vs. saturated:  chi2(91) =  415.43 Prob>chi2 = 0.0000

Factor loadings (pattern matrix) and unique variances

    -------------+--------------------------------------------------+--------------
    Variable   | Factor1    Factor2    Factor3    Factor4    Factor5   | Uniqueness
    -------------+--------------------------------------------------+--------------
    q5x   |   0.5434      0.0279     -0.1698     -0.3151     -0.4230   |     0.3969
    q6x   |   0.5760     -0.3291      0.1505     -0.1260      0.1577   |     0.4965
    q7x   |   0.3225     -0.3880     -0.1223     -0.0653      0.4287   |     0.5424
    q8x   |   0.0140      0.4088      0.3660     -0.4880      0.2602   |     0.3929
    q9x   |   0.5418     -0.3033     -0.1800     -0.0900      0.1008   |     0.5637
    q10x   |   0.4574     -0.3782     -0.1210     -0.0133     -0.2752   |     0.5572
    q11x   |   0.3052      0.1242     -0.4146      0.1010      0.5067   |     0.4526
    q12x   |   0.5546      0.0409      0.1878     -0.3577     -0.1342   |     0.5095
    q13x   |   0.6256      0.1718      0.1810      0.0499     -0.1538   |     0.5202
    q14x   |   0.2189      0.0405      0.7214      0.2019      0.1091   |     0.3774
    q15alt   |   0.4399      0.5237     -0.1655      0.3041      0.1400   |     0.3928
    q16x   |   0.3001     -0.2297      0.2503      0.6258     -0.1364   |     0.3844
    q17x   |   0.5605      0.0816      0.1181      0.0387      0.2696   |     0.5910
    q18alt   |   0.4958      0.4984     -0.2510      0.1521     -0.2245   |     0.3693
    -------------+--------------------------------------------------+--------------

-------------
-> group = 60 second
(obs=304)

Factor analysis/correlation                        Number of obs    =      304
    Method: principal-component factors            Retained factors =        4
    Rotation: (unrotated)                          Number of params =       50

    -------------+------------------------------------------------------------
         Factor  | Eigenvalue     Difference        Proportion   Cumulative
    -------------+------------------------------------------------------------
    Factor1    |      3.14202      1.91383            0.2244       0.2244
    Factor2    |      1.22819      0.09110            0.0877       0.3122
    Factor3    |      1.13709      0.05791            0.0812       0.3934
    Factor4    |      1.07918      0.08669            0.0771       0.4705
    Factor5    |      0.99249      0.08125            0.0709       0.5414
    Factor6    |      0.91124      0.05614            0.0651       0.6064
    Factor7    |      0.85510      0.02622            0.0611       0.6675
    Factor8    |      0.82889      0.03778            0.0592       0.7267
    Factor9    |      0.79111      0.09239            0.0565       0.7832
    Factor10    |      0.69873      0.03993            0.0499       0.8331
    Factor11    |      0.65879      0.04554            0.0471       0.8802
    Factor12    |      0.61325      0.04533            0.0438       0.9240
    Factor13    |      0.56792      0.07195            0.0406       0.9646
    Factor14    |      0.49598            .            0.0354       1.0000
    -------------+------------------------------------------------------------
    LR test: independent vs. saturated:  chi2(91) =  494.23 Prob>chi2 = 0.0000

Factor loadings (pattern matrix) and unique variances

    -------------+----------------------------------------+--------------
    Variable   | Factor1    Factor2    Factor3    Factor4   | Uniqueness
    -------------+----------------------------------------+--------------
    q5x   |   0.6109     -0.0331      0.0866      0.1821   |     0.5850
    q6x   |   0.6376     -0.1892      0.1851     -0.1062   |     0.5121
    q7x   |   0.4117     -0.0187      0.3597     -0.0343   |     0.6995
    q8x   |  -0.0051      0.4799      0.6217      0.1260   |     0.3673
    q9x   |   0.4571      0.0975     -0.3457     -0.3261   |     0.5557
    q10x   |   0.4549     -0.0973     -0.3478     -0.1525   |     0.6394
    q11x   |   0.3353      0.2704     -0.0645      0.2179   |     0.7628
    q12x   |   0.7117     -0.0224      0.1737     -0.1149   |     0.4496
    q13x   |   0.6386     -0.1712      0.0878      0.3102   |     0.4589
    q14x   |   0.3434     -0.1794      0.1338     -0.6399   |     0.4224
    q15alt   |   0.3374      0.6021     -0.2930      0.1956   |     0.3995
    q16x   |   0.2256     -0.4794     -0.2772      0.4945   |     0.3979
    q17x   |   0.5682     -0.0408      0.1350      0.1556   |     0.6330
    q18alt   |   0.3800      0.4609     -0.3133     -0.1209   |     0.5303
    -------------+----------------------------------------+--------------

-------------
-> group = 24 hours/
(obs=291)

Factor analysis/correlation                        Number of obs    =      291
    Method: principal-component factors            Retained factors =        3
    Rotation: (unrotated)                          Number of params =       39

    -------------+------------------------------------------------------------
         Factor  | Eigenvalue     Difference        Proportion   Cumulative
    -------------+------------------------------------------------------------
    Factor1    |      3.13079      1.80053            0.2236       0.2236
    Factor2    |      1.33026      0.14262            0.0950       0.3186
    Factor3    |      1.18764      0.19372            0.0848       0.4035
    Factor4    |      0.99392      0.01639            0.0710       0.4745
    Factor5    |      0.97753      0.06821            0.0698       0.5443
    Factor6    |      0.90932      0.05609            0.0650       0.6092
    Factor7    |      0.85322      0.08546            0.0609       0.6702
    Factor8    |      0.76777      0.01726            0.0548       0.7250
    Factor9    |      0.75050      0.05617            0.0536       0.7786
    Factor10    |      0.69433      0.02467            0.0496       0.8282
    Factor11    |      0.66966      0.02613            0.0478       0.8761
    Factor12    |      0.64353      0.05213            0.0460       0.9220
    Factor13    |      0.59139      0.09127            0.0422       0.9643
    Factor14    |      0.50013            .            0.0357       1.0000
    -------------+------------------------------------------------------------
    LR test: independent vs. saturated:  chi2(91) =  473.93 Prob>chi2 = 0.0000

Factor loadings (pattern matrix) and unique variances

    -------------+------------------------------+--------------
    Variable   | Factor1    Factor2    Factor3   | Uniqueness
    -------------+------------------------------+--------------
    q5x   |   0.6334     -0.1529      0.0761   |     0.5697
    q6x   |   0.5332     -0.2514     -0.2286   |     0.6002
    q7x   |   0.3625     -0.3878      0.1484   |     0.6961
    q8x   |   0.3912      0.4105      0.0330   |     0.6774
    q9x   |   0.4527     -0.2730      0.5513   |     0.4165
    q10x   |   0.2937      0.3129      0.5070   |     0.5588
    q11x   |   0.2884     -0.2151      0.3021   |     0.7793
    q12x   |   0.5737     -0.1589     -0.2746   |     0.5702
    q13x   |   0.5969     -0.1933     -0.0033   |     0.6064
    q14x   |   0.3193      0.3373      0.3671   |     0.6494
    q15alt   |   0.5072      0.3770     -0.1161   |     0.5872
    q16x   |   0.2705      0.5480     -0.1689   |     0.5980
    q17x   |   0.5219     -0.1692     -0.4076   |     0.5328
    q18alt   |   0.6296      0.2419     -0.1890   |     0.5093
    -------------+------------------------------+--------------

.
. *Corrected results
.
.         bysort group: factor q5x q6x q7x q8x q9x q10x q11x q12x q13x q14x q15x q16x q17x q18x, pcf

-------------
-> group = 60 second
(obs=312)

Factor analysis/correlation                        Number of obs    =      312
    Method: principal-component factors            Retained factors =        5
    Rotation: (unrotated)                          Number of params =       60

    -------------+------------------------------------------------------------
         Factor  | Eigenvalue     Difference        Proportion   Cumulative
    -------------+------------------------------------------------------------
    Factor1    |      2.90577      1.56155            0.2076       0.2076
    Factor2    |      1.34422      0.17670            0.0960       0.3036
    Factor3    |      1.16752      0.10541            0.0834       0.3870
    Factor4    |      1.06211      0.03521            0.0759       0.4628
    Factor5    |      1.02690      0.13645            0.0734       0.5362
    Factor6    |      0.89045      0.04229            0.0636       0.5998
    Factor7    |      0.84816      0.02033            0.0606       0.6604
    Factor8    |      0.82783      0.04844            0.0591       0.7195
    Factor9    |      0.77939      0.01701            0.0557       0.7752
    Factor10    |      0.76239      0.05801            0.0545       0.8296
    Factor11    |      0.70438      0.09817            0.0503       0.8799
    Factor12    |      0.60620      0.06013            0.0433       0.9232
    Factor13    |      0.54607      0.01746            0.0390       0.9622
    Factor14    |      0.52862            .            0.0378       1.0000
    -------------+------------------------------------------------------------
    LR test: independent vs. saturated:  chi2(91) =  453.46 Prob>chi2 = 0.0000

Factor loadings (pattern matrix) and unique variances

    -------------+--------------------------------------------------+--------------
    Variable   | Factor1    Factor2    Factor3    Factor4    Factor5   | Uniqueness
    -------------+--------------------------------------------------+--------------
    q5x   |   0.5521      0.0664      0.0878      0.3466      0.1237   |     0.5476
    q6x   |   0.5304      0.0016     -0.1767      0.2705     -0.5660   |     0.2939
    q7x   |   0.3728      0.4702      0.0663     -0.2617      0.2413   |     0.5088
    q8x   |   0.0129      0.3600      0.6598      0.4612      0.1343   |     0.2041
    q9x   |   0.4689      0.3581     -0.0784     -0.2237      0.1312   |     0.5785
    q10x   |   0.4896      0.3465     -0.1772     -0.0575     -0.0512   |     0.6029
    q11x   |   0.3190     -0.4590     -0.3022     -0.1132      0.4652   |     0.3671
    q12x   |   0.5587     -0.1681     -0.2080      0.0940      0.1359   |     0.5890
    q13x   |   0.5417     -0.1778      0.0263      0.2126      0.0990   |     0.6193
    q14x   |   0.2749      0.3590      0.0797     -0.5391     -0.1684   |     0.4702
    q15x   |   0.5191     -0.2869      0.5155     -0.1761      0.0254   |     0.3508
    q16x   |   0.2056      0.3804     -0.4038      0.3526      0.2702   |     0.4526
    q17x   |   0.5263     -0.1088     -0.0681      0.0208     -0.4880   |     0.4680
    q18x   |   0.5909     -0.3200      0.2762     -0.1449      0.1018   |     0.4408
    -------------+--------------------------------------------------+--------------

-------------
-> group = 24 hours/
(obs=302)

Factor analysis/correlation                        Number of obs    =      302
    Method: principal-component factors            Retained factors =        4
    Rotation: (unrotated)                          Number of params =       50

    -------------+------------------------------------------------------------
         Factor  | Eigenvalue     Difference        Proportion   Cumulative
    -------------+------------------------------------------------------------
    Factor1    |      3.00097      1.71171            0.2144       0.2144
    Factor2    |      1.28926      0.12234            0.0921       0.3064
    Factor3    |      1.16692      0.10305            0.0834       0.3898
    Factor4    |      1.06387      0.06446            0.0760       0.4658
    Factor5    |      0.99940      0.10769            0.0714       0.5372
    Factor6    |      0.89172      0.01919            0.0637       0.6009
    Factor7    |      0.87252      0.07870            0.0623       0.6632
    Factor8    |      0.79382      0.01641            0.0567       0.7199
    Factor9    |      0.77742      0.02345            0.0555       0.7754
    Factor10    |      0.75397      0.07378            0.0539       0.8293
    Factor11    |      0.68019      0.05534            0.0486       0.8779
    Factor12    |      0.62485      0.02795            0.0446       0.9225
    Factor13    |      0.59690      0.10872            0.0426       0.9651
    Factor14    |      0.48818            .            0.0349       1.0000
    -------------+------------------------------------------------------------
    LR test: independent vs. saturated:  chi2(91) =  455.44 Prob>chi2 = 0.0000

Factor loadings (pattern matrix) and unique variances

    -------------+----------------------------------------+--------------
    Variable   | Factor1    Factor2    Factor3    Factor4   | Uniqueness
    -------------+----------------------------------------+--------------
    q5x   |   0.5218      0.0131     -0.1736      0.3649   |     0.5642
    q6x   |   0.5826     -0.3029      0.1881      0.1640   |     0.5066
    q7x   |   0.2952     -0.4255     -0.1294      0.1285   |     0.6986
    q8x   |   0.0345      0.4325      0.3666      0.4850   |     0.4421
    q9x   |   0.5522     -0.3308     -0.1428      0.0496   |     0.5628
    q10x   |   0.4722     -0.3958     -0.0915     -0.0057   |     0.6119
    q11x   |   0.3252      0.1170     -0.3542     -0.0401   |     0.7535
    q12x   |   0.5726      0.0714      0.2060      0.3070   |     0.5303
    q13x   |   0.6227      0.1941      0.1389     -0.0278   |     0.5545
    q14x   |   0.2611      0.1107      0.7031     -0.2206   |     0.3767
    q15x   |   0.4465      0.4905     -0.2483     -0.2807   |     0.4196
    q16x   |   0.3196     -0.2097      0.2461     -0.6274   |     0.3997
    q17x   |   0.5747      0.0736      0.0934     -0.0843   |     0.6484
    q18x   |   0.5017      0.4522     -0.3302     -0.1573   |     0.4100
    -------------+----------------------------------------+--------------

-------------
-> group = 60 second
(obs=306)

Factor analysis/correlation                        Number of obs    =      306
    Method: principal-component factors            Retained factors =        4
    Rotation: (unrotated)                          Number of params =       50

    -------------+------------------------------------------------------------
         Factor  | Eigenvalue     Difference        Proportion   Cumulative
    -------------+------------------------------------------------------------
    Factor1    |      3.15406      1.92739            0.2253       0.2253
    Factor2    |      1.22667      0.08963            0.0876       0.3129
    Factor3    |      1.13704      0.06197            0.0812       0.3941
    Factor4    |      1.07507      0.08444            0.0768       0.4709
    Factor5    |      0.99063      0.08196            0.0708       0.5417
    Factor6    |      0.90867      0.05764            0.0649       0.6066
    Factor7    |      0.85103      0.02414            0.0608       0.6674
    Factor8    |      0.82688      0.03450            0.0591       0.7264
    Factor9    |      0.79238      0.09134            0.0566       0.7830
    Factor10    |      0.70104      0.04557            0.0501       0.8331
    Factor11    |      0.65547      0.04476            0.0468       0.8799
    Factor12    |      0.61071      0.03451            0.0436       0.9235
    Factor13    |      0.57620      0.08206            0.0412       0.9647
    Factor14    |      0.49414            .            0.0353       1.0000
    -------------+------------------------------------------------------------
    LR test: independent vs. saturated:  chi2(91) =  499.57 Prob>chi2 = 0.0000

Factor loadings (pattern matrix) and unique variances

    -------------+----------------------------------------+--------------
    Variable   | Factor1    Factor2    Factor3    Factor4   | Uniqueness
    -------------+----------------------------------------+--------------
    q5x   |   0.6054     -0.0415      0.1018      0.1845   |     0.5874
    q6x   |   0.6341     -0.1944      0.1902     -0.1051   |     0.5129
    q7x   |   0.4123     -0.0277      0.3657     -0.0349   |     0.6943
    q8x   |  -0.0017      0.4761      0.6226      0.1169   |     0.3721
    q9x   |   0.4621      0.1037     -0.3474     -0.3202   |     0.5525
    q10x   |   0.4577     -0.0922     -0.3494     -0.1492   |     0.6376
    q11x   |   0.3387      0.2714     -0.0632      0.2173   |     0.7604
    q12x   |   0.7125     -0.0236      0.1687     -0.1178   |     0.4495
    q13x   |   0.6394     -0.1726      0.0860      0.3069   |     0.4597
    q14x   |   0.3486     -0.1721      0.1127     -0.6442   |     0.4212
    q15x   |   0.3397      0.6035     -0.2831      0.2045   |     0.3984
    q16x   |   0.2290     -0.4748     -0.2831      0.4926   |     0.3993
    q17x   |   0.5705     -0.0417      0.1316      0.1502   |     0.6329
    q18x   |   0.3827      0.4641     -0.3102     -0.1138   |     0.5290
    -------------+----------------------------------------+--------------

-------------
-> group = 24 hours/
(obs=300)

Factor analysis/correlation                        Number of obs    =      300
    Method: principal-component factors            Retained factors =        4
    Rotation: (unrotated)                          Number of params =       50

    -------------+------------------------------------------------------------
         Factor  | Eigenvalue     Difference        Proportion   Cumulative
    -------------+------------------------------------------------------------
    Factor1    |      3.20840      1.90790            0.2292       0.2292
    Factor2    |      1.30050      0.12868            0.0929       0.3221
    Factor3    |      1.17182      0.12678            0.0837       0.4058
    Factor4    |      1.04503      0.07930            0.0746       0.4804
    Factor5    |      0.96574      0.06876            0.0690       0.5494
    Factor6    |      0.89698      0.05236            0.0641       0.6135
    Factor7    |      0.84462      0.08634            0.0603       0.6738
    Factor8    |      0.75828      0.01791            0.0542       0.7280
    Factor9    |      0.74037      0.03031            0.0529       0.7808
    Factor10    |      0.71006      0.05721            0.0507       0.8316
    Factor11    |      0.65285      0.02390            0.0466       0.8782
    Factor12    |      0.62895      0.04700            0.0449       0.9231
    Factor13    |      0.58195      0.08751            0.0416       0.9647
    Factor14    |      0.49444            .            0.0353       1.0000
    -------------+------------------------------------------------------------
    LR test: independent vs. saturated:  chi2(91) =  511.50 Prob>chi2 = 0.0000

Factor loadings (pattern matrix) and unique variances

    -------------+----------------------------------------+--------------
    Variable   | Factor1    Factor2    Factor3    Factor4   | Uniqueness
    -------------+----------------------------------------+--------------
    q5x   |   0.6135     -0.1593      0.0453      0.0911   |     0.5879
    q6x   |   0.5324     -0.2479     -0.2187      0.2575   |     0.5410
    q7x   |   0.3718     -0.3893      0.1549      0.4587   |     0.4758
    q8x   |   0.3688      0.3816      0.0463      0.6402   |     0.3064
    q9x   |   0.4786     -0.2708      0.5299     -0.1609   |     0.3909
    q10x   |   0.3077      0.2945      0.5383      0.0328   |     0.5278
    q11x   |   0.3066     -0.2218      0.2905     -0.1888   |     0.7368
    q12x   |   0.5875     -0.1486     -0.2634     -0.1378   |     0.5444
    q13x   |   0.6046     -0.1894     -0.0197     -0.0744   |     0.5926
    q14x   |   0.3469      0.3281      0.3515     -0.3267   |     0.5417
    q15x   |   0.5134      0.3862     -0.1245     -0.1947   |     0.5338
    q16x   |   0.2862      0.5541     -0.1486     -0.0095   |     0.5889
    q17x   |   0.5313     -0.1571     -0.4149     -0.3362   |     0.4079
    q18x   |   0.6307      0.2464     -0.1946      0.0725   |     0.4984
    -------------+----------------------------------------+--------------

.
.
. *2.5.2 Chronbach's Alpha
. *Published results (see documentation)
.         bysort group: alpha q5x q6x q7x q8x q9x q10x q11x q12x q13x q14x q15alt q16x q17x q18alt if mi(q15alt, q18alt)==0

-------------
-> group = 60 second

Test scale = mean(unstandardized items)

Average interitem covariance:     .0261945
Number of items in the scale:           14
Scale reliability coefficient:      0.6716

-------------
-> group = 24 hours/

Test scale = mean(unstandardized items)

Average interitem covariance:     .0289264
Number of items in the scale:           14
Scale reliability coefficient:      0.6782

-------------
-> group = 60 second

Test scale = mean(unstandardized items)
Reversed item:  q8x

Average interitem covariance:     .0315682
Number of items in the scale:           14
Scale reliability coefficient:      0.7089

-------------
-> group = 24 hours/

Test scale = mean(unstandardized items)

Average interitem covariance:     .0340583
Number of items in the scale:           14
Scale reliability coefficient:      0.7147

.
. *Corrected results
.         bysort group: alpha q5x q6x q7x q8x q9x q10x q11x q12x q13x q14x q15x q16x q17x q18x

-------------
-> group = 60 second

Test scale = mean(unstandardized items)

Average interitem covariance:     .0265439
Number of items in the scale:           14
Scale reliability coefficient:      0.6754

-------------
-> group = 24 hours/

Test scale = mean(unstandardized items)

Average interitem covariance:     .0303805
Number of items in the scale:           14
Scale reliability coefficient:      0.6918

-------------
-> group = 60 second

Test scale = mean(unstandardized items)
Reversed item:  q8x

Average interitem covariance:     .0317586
Number of items in the scale:           14
Scale reliability coefficient:      0.7108

-------------
-> group = 24 hours/

Test scale = mean(unstandardized items)

Average interitem covariance:      .035537
Number of items in the scale:           14
Scale reliability coefficient:      0.7257

.
. *2.5.3 Completion time
.         tab  dt_end

       date |
  interview |
      ended |      Freq.     Percent        Cum.
------------+-----------------------------------
   2.00e+07 |        835       69.41       69.41
   2.00e+07 |         68        5.65       75.06
   2.00e+07 |        154       12.80       87.86
   2.00e+07 |         34        2.83       90.69
   2.00e+07 |         66        5.49       96.18
   2.00e+07 |         17        1.41       97.59
   2.00e+07 |         13        1.08       98.67
   2.00e+07 |         16        1.33      100.00
------------+-----------------------------------
      Total |      1,203      100.00

.
. *2.5.4 Number not completing knowledge questions
.         tab q18 if q5!=-2

  in august |
  2004, the |
     census |
     bureau |
   reported |
   how many |
  americans |
    live in |
  poverty.  |      Freq.     Percent        Cum.
------------+-----------------------------------
  not asked |         24        1.97        1.97
    refused |         20        1.64        3.61
          0 |          2        0.16        3.77
          1 |          2        0.16        3.93
          2 |          4        0.33        4.26
          3 |          1        0.08        4.34
          4 |          1        0.08        4.43
          5 |         18        1.48        5.90
          6 |          1        0.08        5.98
        6.5 |          1        0.08        6.07
          7 |          9        0.74        6.80
        7.5 |          1        0.08        6.89
          8 |         11        0.90        7.79
          9 |          8        0.66        8.44
         10 |         56        4.59       13.03
         11 |          4        0.33       13.36
         12 |         27        2.21       15.57
       12.1 |          1        0.08       15.66
       12.5 |          9        0.74       16.39
         13 |         14        1.15       17.54
         14 |          9        0.74       18.28
         15 |         84        6.89       25.16
         16 |          4        0.33       25.49
         17 |         16        1.31       26.80
         18 |         25        2.05       28.85
         19 |          3        0.25       29.10
         20 |        132       10.82       39.92
         21 |          6        0.49       40.41
         22 |         12        0.98       41.39
         23 |         18        1.48       42.87
         24 |          5        0.41       43.28
         25 |        113        9.26       52.54
         26 |          4        0.33       52.87
         27 |          7        0.57       53.44
         28 |          7        0.57       54.02
         29 |          5        0.41       54.43
         30 |         93        7.62       62.05
         32 |          4        0.33       62.38
         33 |          8        0.66       63.03
         34 |          5        0.41       63.44
         35 |         79        6.48       69.92
         36 |          4        0.33       70.25
         37 |          3        0.25       70.49
         38 |          8        0.66       71.15
         39 |          3        0.25       71.39
         40 |         73        5.98       77.38
         42 |          2        0.16       77.54
         43 |         10        0.82       78.36
         44 |          3        0.25       78.61
         45 |         33        2.70       81.31
         46 |          2        0.16       81.48
         48 |          8        0.66       82.13
         49 |          1        0.08       82.21
         50 |         50        4.10       86.31
         51 |          3        0.25       86.56
         52 |          2        0.16       86.72
         55 |         11        0.90       87.62
         56 |          1        0.08       87.70
         57 |          1        0.08       87.79
         58 |          2        0.16       87.95
         60 |         32        2.62       90.57
         63 |          2        0.16       90.74
         65 |         28        2.30       93.03
         66 |          1        0.08       93.11
         67 |          1        0.08       93.20
         68 |          2        0.16       93.36
         69 |          1        0.08       93.44
         70 |         19        1.56       95.00
         72 |          2        0.16       95.16
         73 |          1        0.08       95.25
         75 |         23        1.89       97.13
         76 |          1        0.08       97.21
         78 |          2        0.16       97.38
         80 |         15        1.23       98.61
         85 |          6        0.49       99.10
         87 |          1        0.08       99.18
         90 |          3        0.25       99.43
         95 |          1        0.08       99.51
         98 |          2        0.16       99.67
         99 |          4        0.33      100.00
------------+-----------------------------------
      Total |      1,220      100.00

.
. *2.5.5 Number not completing survey after starting knowledge section
.         tab group if tm_end==. & q5!=-2

               data-only: group  |      Freq.     Percent        Cum.
---------------------------------+-----------------------------------
               60 seconds/no pay |          3       17.65       17.65
                 24 hours/no pay |          7       41.18       58.82
60 seconds/$1 per correct answer |          4       23.53       82.35
  24 hours/$1 per correct answer |          3       17.65      100.00
---------------------------------+-----------------------------------
                           Total |         17      100.00

.
. *2.5.6 Distribution of correct answers by condition
.
.         tab allknow if group==1

    allknow |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |          6        1.92        1.92
          1 |         40       12.82       14.74
          2 |         40       12.82       27.56
          3 |         43       13.78       41.35
          4 |         43       13.78       55.13
          5 |         36       11.54       66.67
          6 |         25        8.01       74.68
          7 |         24        7.69       82.37
          8 |         23        7.37       89.74
          9 |         15        4.81       94.55
         10 |         10        3.21       97.76
         11 |          5        1.60       99.36
         12 |          2        0.64      100.00
------------+-----------------------------------
      Total |        312      100.00

.         tab allknow if group==4

    allknow |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |          8        2.67        2.67
          1 |         11        3.67        6.33
          2 |         25        8.33       14.67
          3 |         37       12.33       27.00
          4 |         38       12.67       39.67
          5 |         46       15.33       55.00
          6 |         33       11.00       66.00
          7 |         23        7.67       73.67
          8 |         22        7.33       81.00
          9 |         17        5.67       86.67
         10 |         18        6.00       92.67
         11 |          8        2.67       95.33
         12 |          4        1.33       96.67
         13 |          8        2.67       99.33
         14 |          2        0.67      100.00
------------+-----------------------------------
      Total |        300      100.00

.
. *2.5.7 ANOVA: Treatment effects
. anova allknow time pay time*pay

                           Number of obs =    1220     R-squared     =  0.0187
                           Root MSE      = 2.94093     Adj R-squared =  0.0163

                  Source |  Partial SS    df       MS           F     Prob > F
              -----------+----------------------------------------------------
                   Model |  200.860985     3  66.9536616       7.74     0.0000
                         |
                    time |  148.757332     1  148.757332      17.20     0.0000
                     pay |  47.1473245     1  47.1473245       5.45     0.0197
                time*pay |  3.74843714     1  3.74843714       0.43     0.5105
                         |
                Residual |  10517.2792  1216  8.64907827
              -----------+----------------------------------------------------
                   Total |  10718.1402  1219  8.79256781

.
. *2.5.8 Pairwise comparisons of coefficients
.
.         * Compare column 1 to other columns
.         recode group 1=0 2=1 3=2 4=3, gen(test)
(1220 differences between group and test)

.         xi: regress allknow i.test*intsome i.test*intmost i.test*hsonly i.test*somecol i.test*college i.test*female i.test*age35_44 i.test*age45_59 i.test*age60p i.test**minority i.test*income i.test**employ i.test**married
i.test            _Itest_0-3          (naturally coded; _Itest_0 omitted)
i.test*intsome    _ItesXintso_#       (coded as above)
i.test*intmost    _ItesXintmo_#       (coded as above)
i.test*hsonly     _ItesXhsonl_#       (coded as above)
i.test*somecol    _ItesXsomec_#       (coded as above)
i.test*college    _ItesXcolle_#       (coded as above)
i.test*female     _ItesXfemal_#       (coded as above)
i.test*age35_44   _ItesXage35_#       (coded as above)
i.test*age45_59   _ItesXage45_#       (coded as above)
i.test*age60p     _ItesXage60_#       (coded as above)
i.test*minority   _ItesXminor_#       (coded as above)
i.test*income     _ItesXincom_#       (coded as above)
i.test*employ     _ItesXemplo_#       (coded as above)
i.test*married    _ItesXmarri_#       (coded as above)

      Source |       SS       df       MS              Number of obs =    1220
-------------+------------------------------           F( 55,  1164) =   10.08
       Model |  3458.24843    55  62.8772442           Prob > F      =  0.0000
    Residual |  7259.89173  1164  6.23702039           R-squared     =  0.3227
-------------+------------------------------           Adj R-squared =  0.2906
       Total |  10718.1402  1219  8.79256781           Root MSE      =  2.4974

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
    _Itest_1 |  (dropped)
    _Itest_2 |   .5475507   .8822544     0.62   0.535    -1.183436    2.278537
    _Itest_3 |   .3459827   .8945278     0.39   0.699    -1.409085     2.10105
     intsome |   .0339096   .3743504     0.09   0.928    -.7005674    .7683865
_ItesXints~1 |   .8253992   .5329341     1.55   0.122    -.2202197    1.871018
_ItesXints~2 |   1.470481   .5331722     2.76   0.006     .4243949    2.516567
_ItesXints~3 |  -.0428676   .5340327    -0.08   0.936    -1.090642    1.004907
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
     intmost |   1.937805   .3989989     4.86   0.000     1.154968    2.720643
_ItesXintm~1 |  -.6754497   .5662149    -1.19   0.233    -1.786366    .4354663
_ItesXintm~2 |   .3179205   .5740731     0.55   0.580    -.8084134    1.444254
_ItesXintm~3 |  -.8567441    .572763    -1.50   0.135    -1.980508    .2670194
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      hsonly |   .2521308   .4251489     0.59   0.553    -.5820131    1.086275
_ItesXhson~1 |   .2725687   .6149901     0.44   0.658    -.9340443    1.479182
_ItesXhson~2 |   .3404326   .6218243     0.55   0.584    -.8795892    1.560454
_ItesXhson~3 |   .1771236   .6282145     0.28   0.778    -1.055436    1.409683
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
     somecol |   .5057705   .5058857     1.00   0.318    -.4867794     1.49832
_ItesXsome~1 |   .2553775   .6952378     0.37   0.713    -1.108682    1.619437
_ItesXsome~2 |   .3865114   .6955992     0.56   0.579    -.9782572     1.75128
_ItesXsome~3 |   1.887595   .7269834     2.60   0.010     .4612506    3.313939
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
     college |   1.829173   .4649713     3.93   0.000      .916897    2.741448
_ItesXcoll~1 |  -.0283551    .653671    -0.04   0.965     -1.31086     1.25415
_ItesXcoll~2 |  -.0960566   .6737639    -0.14   0.887    -1.417984    1.225871
_ItesXcoll~3 |    .368477   .6994832     0.53   0.598    -1.003912    1.740866
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      female |  -.3757411   .2923229    -1.29   0.199    -.9492799    .1977976
_ItesXfema~1 |  -.0964276   .4211968    -0.23   0.819    -.9228174    .7299623
_ItesXfema~2 |  -.5151526   .4130313    -1.25   0.213    -1.325522    .2952164
_ItesXfema~3 |    .059409   .4174504     0.14   0.887    -.7596304    .8784484
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
    age35_44 |  -.2903481   .4247388    -0.68   0.494    -1.123687    .5429912
_ItesXage3~1 |   .5533139   .6134911     0.90   0.367    -.6503582    1.756986
_ItesXage3~2 |  -.0805608    .607019    -0.13   0.894    -1.271535    1.110413
_ItesXage3~3 |   .7263266   .6054868     1.20   0.231     -.461641    1.914294
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
    age45_59 |    -.22744   .4290334    -0.53   0.596    -1.069205    .6143253
_ItesXage4~1 |   .7726343   .6125621     1.26   0.207     -.429215    1.974484
_ItesXage4~2 |   .6070565   .6121689     0.99   0.322    -.5940215    1.808134
_ItesXage4~3 |   .8550244   .6001033     1.42   0.154    -.3223807    2.032429
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      age60p |  -.6343792   .4648495    -1.36   0.173    -1.546416    .2776575
_ItesXage6~1 |   2.185917   .6677034     3.27   0.001     .8758807    3.495954
_ItesXage6~2 |   .3056693    .657592     0.46   0.642     -.984529    1.595868
_ItesXage6~3 |   1.683341   .6528275     2.58   0.010     .4024913    2.964192
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
    minority |   -.840479   .3706898    -2.27   0.024    -1.567774    -.113184
_ItesXmino~1 |  -.2407097   .5117964    -0.47   0.638    -1.244856    .7634369
_ItesXmino~2 |  -.9730117   .5195226    -1.87   0.061    -1.992317    .0462938
_ItesXmino~3 |  -1.082392   .5284527    -2.05   0.041    -2.119218   -.0455655
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      income |   .1830259    .040113     4.56   0.000     .1043241    .2617278
_ItesXinco~1 |  -.0774944   .0583283    -1.33   0.184    -.1919348    .0369461
_ItesXinco~2 |   -.065287   .0553204    -1.18   0.238    -.1738258    .0432518
_ItesXinco~3 |  -.0675793   .0590121    -1.15   0.252    -.1833614    .0482028
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      employ |  -.7274535    .355654    -2.05   0.041    -1.425248   -.0296589
_ItesXempl~1 |   .7702177   .5089531     1.51   0.130    -.2283503    1.768786
_ItesXempl~2 |   .1557327    .484885     0.32   0.748    -.7956137    1.107079
_ItesXempl~3 |    .578636   .4990056     1.16   0.246    -.4004151    1.557687
    _Itest_1 |  -.2106448   .9473313    -0.22   0.824    -2.069313    1.648023
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
     married |    -.07903   .3113077    -0.25   0.800     -.689817     .531757
_ItesXmarr~1 |   .4046523   .4434983     0.91   0.362    -.4654932    1.274798
_ItesXmarr~2 |   .0665951   .4399638     0.15   0.880    -.7966156    .9298059
_ItesXmarr~3 |   .2418456   .4531683     0.53   0.594    -.6472724    1.130964
       _cons |   2.468748   .6221537     3.97   0.000      1.24808    3.689416
-------------+----------------------------------------------------------------

.         drop test

.
.         * Compare column 2 to other columns
.         recode group 1=1 2=2 3=0 4=3, gen(test)
(606 differences between group and test)

.         xi: regress allknow i.test*intsome i.test*intmost i.test*hsonly i.test*somecol i.test*college i.test*female i.test*age35_44 i.test*age45_59 i.test*age60p i.test**minority i.test*income i.test**employ i.test**married
i.test            _Itest_0-3          (naturally coded; _Itest_0 omitted)
i.test*intsome    _ItesXintso_#       (coded as above)
i.test*intmost    _ItesXintmo_#       (coded as above)
i.test*hsonly     _ItesXhsonl_#       (coded as above)
i.test*somecol    _ItesXsomec_#       (coded as above)
i.test*college    _ItesXcolle_#       (coded as above)
i.test*female     _ItesXfemal_#       (coded as above)
i.test*age35_44   _ItesXage35_#       (coded as above)
i.test*age45_59   _ItesXage45_#       (coded as above)
i.test*age60p     _ItesXage60_#       (coded as above)
i.test*minority   _ItesXminor_#       (coded as above)
i.test*income     _ItesXincom_#       (coded as above)
i.test*employ     _ItesXemplo_#       (coded as above)
i.test*married    _ItesXmarri_#       (coded as above)

      Source |       SS       df       MS              Number of obs =    1220
-------------+------------------------------           F( 55,  1164) =   10.08
       Model |  3458.24843    55  62.8772442           Prob > F      =  0.0000
    Residual |  7259.89173  1164  6.23702039           R-squared     =  0.3227
-------------+------------------------------           Adj R-squared =  0.2906
       Total |  10718.1402  1219  8.79256781           Root MSE      =  2.4974

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
     intsome |    1.50439   .3796503     3.96   0.000     .7595149    2.249266
_ItesXints~1 |  -1.470481   .5331722    -2.76   0.006    -2.516567   -.4243949
_ItesXints~2 |  -.6450817   .5366703    -1.20   0.230    -1.698031    .4078676
_ItesXints~3 |  -1.513348   .5377612    -2.81   0.005    -2.568438   -.4582588
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
     intmost |   2.255726   .4127467     5.47   0.000     1.445915    3.065536
_ItesXintm~1 |  -.3179205   .5740731    -0.55   0.580    -1.444254    .8084134
_ItesXintm~2 |  -.9933702   .5759853    -1.72   0.085    -2.123456    .1367154
_ItesXintm~3 |  -1.174665   .5824236    -2.02   0.044    -2.317382    -.031947
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      hsonly |   .5925634   .4537773     1.31   0.192    -.2977494    1.482876
_ItesXhson~1 |  -.3404326   .6218243    -0.55   0.584    -1.560454    .8795892
_ItesXhson~2 |  -.0678639   .6351181    -0.11   0.915    -1.313968     1.17824
_ItesXhson~3 |   -.163309   .6479318    -0.25   0.801    -1.434554    1.107936
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
     somecol |   .8922819   .4774284     1.87   0.062    -.0444347    1.828998
_ItesXsome~1 |  -.3865114   .6955992    -0.56   0.579     -1.75128    .9782572
_ItesXsome~2 |  -.1311339   .6748135    -0.19   0.846    -1.455121    1.192853
_ItesXsome~3 |   1.501084    .707476     2.12   0.034     .1130127    2.889154
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
     college |   1.733116   .4876059     3.55   0.000     .7764311    2.689801
_ItesXcoll~1 |   .0960566   .6737639     0.14   0.887    -1.225871    1.417984
_ItesXcoll~2 |   .0677016   .6699604     0.10   0.920    -1.246764    1.382167
_ItesXcoll~3 |   .4645337   .7147293     0.65   0.516    -.9377681    1.866835
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      female |  -.8908938   .2917913    -3.05   0.002    -1.463389   -.3183981
_ItesXfema~1 |   .5151526   .4130313     1.25   0.213    -.2952164    1.325522
_ItesXfema~2 |   .4187251    .420828     1.00   0.320    -.4069411    1.244391
_ItesXfema~3 |   .5745616   .4170783     1.38   0.169    -.2437477    1.392871
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |   -.201568   .8968848    -0.22   0.822     -1.96126    1.558124
    age35_44 |  -.3709089   .4336693    -0.86   0.393     -1.22177    .4799519
_ItesXage3~1 |   .0805608    .607019     0.13   0.894    -1.110413    1.271535
_ItesXage3~2 |   .6338747   .6197074     1.02   0.307    -.5819938    1.849743
_ItesXage3~3 |   .8068874   .6117845     1.32   0.187    -.3934363    2.007211
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
    age45_59 |   .3796165   .4366705     0.87   0.385    -.4771329    1.236366
_ItesXage4~1 |  -.6070565   .6121689    -0.99   0.322    -1.808134    .5940215
_ItesXage4~2 |   .1655778   .6179351     0.27   0.789    -1.046813    1.377969
_ItesXage4~3 |   .2479679   .6055868     0.41   0.682     -.940196    1.436132
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      age60p |  -.3287099    .465126    -0.71   0.480    -1.241289    .5838692
_ItesXage6~1 |  -.3056693    .657592    -0.46   0.642    -1.595868     .984529
_ItesXage6~2 |   1.880248   .6678959     2.82   0.005     .5698337    3.190663
_ItesXage6~3 |   1.377672   .6530244     2.11   0.035     .0964357    2.658909
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
    minority |  -1.813491   .3639956    -4.98   0.000    -2.527652    -1.09933
_ItesXmino~1 |   .9730117   .5195226     1.87   0.061    -.0462938    1.992317
_ItesXmino~2 |    .732302   .5069688     1.44   0.149    -.2623729    1.726977
_ItesXmino~3 |  -.1093801   .5237786    -0.21   0.835    -1.137036    .9182757
    _Itest_1 |  -.5475507   .8822544    -0.62   0.535    -2.278537    1.183436
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      income |   .1177389   .0380958     3.09   0.002     .0429948    .1924831
_ItesXinco~1 |    .065287   .0553204     1.18   0.238    -.0432518    .1738258
_ItesXinco~2 |  -.0122074   .0569599    -0.21   0.830     -.123963    .0995483
_ItesXinco~3 |  -.0022923     .05766    -0.04   0.968    -.1154214    .1108368
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      employ |  -.5717208   .3295811    -1.73   0.083     -1.21836    .0749187
_ItesXempl~1 |  -.1557327    .484885    -0.32   0.748    -1.107079    .7956137
_ItesXempl~2 |    .614485   .4910877     1.25   0.211    -.3490312    1.578001
_ItesXempl~3 |   .4229033   .4807708     0.88   0.379    -.5203709    1.366178
    _Itest_1 |  (dropped)
    _Itest_2 |  -.7581955   .9495573    -0.80   0.425    -2.621231     1.10484
    _Itest_3 |  (dropped)
     married |  -.0124349   .3108949    -0.04   0.968     -.622412    .5975422
_ItesXmarr~1 |  -.0665951   .4399638    -0.15   0.880    -.9298059    .7966156
_ItesXmarr~2 |   .3380572   .4432087     0.76   0.446      -.53152    1.207634
_ItesXmarr~3 |   .1752504   .4528848     0.39   0.699    -.7133114    1.063812
       _cons |   3.016299   .6255379     4.82   0.000     1.788991    4.243606
-------------+----------------------------------------------------------------

.         drop test

.
.         * Compare column 3 to other columns
.         recode group 1=1 2=0 3=2 4=3, gen(test)
(908 differences between group and test)

.         xi: regress allknow i.test*intsome i.test*intmost i.test*hsonly i.test*somecol i.test*college i.test*female i.test*age35_44 i.test*age45_59 i.test*age60p i.test**minority i.test*income i.test**employ i.test**married
i.test            _Itest_0-3          (naturally coded; _Itest_0 omitted)
i.test*intsome    _ItesXintso_#       (coded as above)
i.test*intmost    _ItesXintmo_#       (coded as above)
i.test*hsonly     _ItesXhsonl_#       (coded as above)
i.test*somecol    _ItesXsomec_#       (coded as above)
i.test*college    _ItesXcolle_#       (coded as above)
i.test*female     _ItesXfemal_#       (coded as above)
i.test*age35_44   _ItesXage35_#       (coded as above)
i.test*age45_59   _ItesXage45_#       (coded as above)
i.test*age60p     _ItesXage60_#       (coded as above)
i.test*minority   _ItesXminor_#       (coded as above)
i.test*income     _ItesXincom_#       (coded as above)
i.test*employ     _ItesXemplo_#       (coded as above)
i.test*married    _ItesXmarri_#       (coded as above)

      Source |       SS       df       MS              Number of obs =    1220
-------------+------------------------------           F( 55,  1164) =   10.08
       Model |  3458.24843    55  62.8772442           Prob > F      =  0.0000
    Residual |  7259.89173  1164  6.23702039           R-squared     =  0.3227
-------------+------------------------------           Adj R-squared =  0.2906
       Total |  10718.1402  1219  8.79256781           Root MSE      =  2.4974

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
     intsome |   .8593088    .379316     2.27   0.024     .1150893    1.603528
_ItesXints~1 |  -.8253992   .5329341    -1.55   0.122    -1.871018    .2202197
_ItesXints~2 |   .6450817   .5366703     1.20   0.230    -.4078676    1.698031
_ItesXints~3 |  -.8682667   .5375252    -1.62   0.107    -1.922893    .1863599
    _Itest_1 |   .2106448   .9473313     0.22   0.824    -1.648023    2.069313
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
     intmost |   1.262355   .4017453     3.14   0.002     .4741296    2.050581
_ItesXintm~1 |   .6754497   .5662149     1.19   0.233    -.4354663    1.786366
_ItesXintm~2 |   .9933702   .5759853     1.72   0.085    -.1367154    2.123456
_ItesXintm~3 |  -.1812944   .5746796    -0.32   0.752    -1.308818    .9462294
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      hsonly |   .5246996   .4443661     1.18   0.238    -.3471484    1.396548
_ItesXhson~1 |  -.2725687   .6149901    -0.44   0.658    -1.479182    .9340443
_ItesXhson~2 |   .0678639   .6351181     0.11   0.915     -1.17824    1.313968
_ItesXhson~3 |  -.0954451   .6413759    -0.15   0.882    -1.353827    1.162937
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
     somecol |    .761148   .4769018     1.60   0.111    -.1745352    1.696831
_ItesXsome~1 |  -.2553775   .6952378    -0.37   0.713    -1.619437    1.108682
_ItesXsome~2 |   .1311339   .6748135     0.19   0.846    -1.192853    1.455121
_ItesXsome~3 |   1.632217   .7071207     2.31   0.021     .2448437    3.019591
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |   .5566275   .9609715     0.58   0.563    -1.328803    2.442057
     college |   1.800817   .4594426     3.92   0.000     .8993892    2.702246
_ItesXcoll~1 |   .0283551    .653671     0.04   0.965     -1.25415     1.31086
_ItesXcoll~2 |  -.0677016   .6699604    -0.10   0.920    -1.382167    1.246764
_ItesXcoll~3 |   .3968321   .6958203     0.57   0.569    -.9683702    1.762034
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      female |  -.4721687   .3032393    -1.56   0.120    -1.067125     .122788
_ItesXfema~1 |   .0964276   .4211968     0.23   0.819    -.7299623    .9228174
_ItesXfema~2 |  -.4187251    .420828    -1.00   0.320    -1.244391    .4069411
_ItesXfema~3 |   .1558365   .4251661     0.37   0.714    -.6783411    .9900142
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
    age35_44 |   .2629658   .4426831     0.59   0.553    -.6055802    1.131512
_ItesXage3~1 |  -.5533139   .6134911    -0.90   0.367    -1.756986    .6503582
_ItesXage3~2 |  -.6338747   .6197074    -1.02   0.307    -1.849743    .5819938
_ItesXage3~3 |   .1730127   .6182067     0.28   0.780    -1.039911    1.385937
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
    age45_59 |   .5451943   .4372215     1.25   0.213    -.3126361    1.403025
_ItesXage4~1 |  -.7726343   .6125621    -1.26   0.207    -1.974484     .429215
_ItesXage4~2 |  -.1655778   .6179351    -0.27   0.789    -1.377969    1.046813
_ItesXage4~3 |   .0823901   .6059842     0.14   0.892    -1.106553    1.271334
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      age60p |   1.551538   .4793148     3.24   0.001     .6111206    2.491956
_ItesXage6~1 |  -2.185917   .6677034    -3.27   0.001    -3.495954   -.8758807
_ItesXage6~2 |  -1.880248   .6678959    -2.82   0.005    -3.190663   -.5698337
_ItesXage6~3 |   -.502576   .6632053    -0.76   0.449    -1.803788    .7986356
    _Itest_1 |  (dropped)
    _Itest_2 |   .7581955   .9495573     0.80   0.425     -1.10484    2.621231
    _Itest_3 |  (dropped)
    minority |  -1.081189   .3528804    -3.06   0.002    -1.773542   -.3888359
_ItesXmino~1 |   .2407097   .5117964     0.47   0.638    -.7634369    1.244856
_ItesXmino~2 |   -.732302   .5069688    -1.44   0.149    -1.726977    .2623729
_ItesXmino~3 |   -.841682   .5161161    -1.63   0.103    -1.854304    .1709399
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      income |   .1055315   .0423455     2.49   0.013     .0224495    .1886136
_ItesXinco~1 |   .0774944   .0583283     1.33   0.184    -.0369461    .1919348
_ItesXinco~2 |   .0122074   .0569599     0.21   0.830    -.0995483     .123963
_ItesXinco~3 |   .0099151   .0605518     0.16   0.870    -.1088878     .128718
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
      employ |   .0427641   .3640652     0.12   0.907    -.6715332    .7570615
_ItesXempl~1 |  -.7702177   .5089531    -1.51   0.130    -1.768786    .2283503
_ItesXempl~2 |   -.614485   .4910877    -1.25   0.211    -1.578001    .3490312
_ItesXempl~3 |  -.1915816   .5050349    -0.38   0.705    -1.182462    .7992989
    _Itest_1 |  (dropped)
    _Itest_2 |  (dropped)
    _Itest_3 |  (dropped)
     married |   .3256223    .315877     1.03   0.303    -.2941296    .9453743
_ItesXmarr~1 |  -.4046523   .4434983    -0.91   0.362    -1.274798    .4654932
_ItesXmarr~2 |  -.3380572   .4432087    -0.76   0.446    -1.207634      .53152
_ItesXmarr~3 |  -.1628068   .4563193    -0.36   0.721    -1.058107    .7324935
       _cons |   2.258103   .7143958     3.16   0.002     .8564555    3.659751
-------------+----------------------------------------------------------------

.         drop test

.
.         * (Column 4 comparisons implicit in tests above)
.
.
. *2.5.9 Alternative specification of political interest variable
.
.         bysort group: regress allknow polint2 hsonly somecol college female age35_44 age45_59 age60p minority income employ married

-------------
-> group = 60 second

      Source |       SS       df       MS              Number of obs =     311
-------------+------------------------------           F( 12,   298) =   12.37
       Model |  789.473599    12  65.7894666           Prob > F      =  0.0000
    Residual |  1585.29167   298  5.31977072           R-squared     =  0.3324
-------------+------------------------------           Adj R-squared =  0.3056
       Total |  2374.76527   310  7.66053314           Root MSE      =  2.3065

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
     polint2 |   .7779117   .1461891     5.32   0.000      .490218    1.065605
      hsonly |   .4526005   .3921831     1.15   0.249    -.3191988      1.2244
     somecol |   .6927175   .4656867     1.49   0.138    -.2237337    1.609169
     college |    1.94731   .4293043     4.54   0.000     1.102458    2.792162
      female |  -.4401321   .2699681    -1.63   0.104    -.9714177    .0911534
    age35_44 |  -.2747334   .3916553    -0.70   0.484    -1.045494    .4960271
    age45_59 |  -.2511356   .3966655    -0.63   0.527    -1.031756    .5294849
      age60p |  -.6945986   .4272986    -1.63   0.105    -1.535504    .1463065
    minority |  -.7139862   .3435828    -2.08   0.039    -1.390142   -.0378302
      income |    .177063   .0371002     4.77   0.000     .1040514    .2500745
      employ |  -.7530953   .3287037    -2.29   0.023     -1.39997   -.1062207
     married |  -.0310427   .2881494    -0.11   0.914    -.5981082    .5360228
       _cons |   1.604134   .5931158     2.70   0.007     .4369078     2.77136
-------------+----------------------------------------------------------------

-------------
-> group = 24 hours/

      Source |       SS       df       MS              Number of obs =     301
-------------+------------------------------           F( 12,   288) =    7.51
       Model |  616.836389    12  51.4030324           Prob > F      =  0.0000
    Residual |  1971.23006   288  6.84454881           R-squared     =  0.2383
-------------+------------------------------           Adj R-squared =  0.2066
       Total |  2588.06645   300  8.62688815           Root MSE      =  2.6162

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
     polint2 |   .5778346   .1733617     3.33   0.001      .236618    .9190513
      hsonly |   .5449789   .4651767     1.17   0.242    -.3705982    1.460556
     somecol |    .731982   .5026322     1.46   0.146    -.2573163     1.72128
     college |   1.781942   .4806967     3.71   0.000      .835818    2.728066
      female |  -.4397904   .3185743    -1.38   0.169    -1.066819    .1872387
    age35_44 |   .2552858   .4633827     0.55   0.582    -.6567604    1.167332
    age45_59 |   .4778499   .4598708     1.04   0.300    -.4272839    1.382984
      age60p |   1.480014   .5027478     2.94   0.004     .4904878     2.46954
    minority |   -1.07934   .3689083    -2.93   0.004    -1.805438   -.3532412
      income |   .1002793   .0436394     2.30   0.022     .0143866    .1861719
      employ |   .0355681   .3817342     0.09   0.926    -.7157745    .7869107
     married |   .3169801   .3307572     0.96   0.339    -.3340278    .9679881
       _cons |   1.969566   .7492173     2.63   0.009     .4949298    3.444202
-------------+----------------------------------------------------------------

-------------
-> group = 60 second

      Source |       SS       df       MS              Number of obs =     305
-------------+------------------------------           F( 12,   292) =   14.97
       Model |   1013.8573    12  84.4881083           Prob > F      =  0.0000
    Residual |  1647.50008   292  5.64212355           R-squared     =  0.3810
-------------+------------------------------           Adj R-squared =  0.3555
       Total |  2661.35738   304  8.75446506           Root MSE      =  2.3753

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
     polint2 |   .9096663   .1623482     5.60   0.000     .5901453    1.229187
      hsonly |   .7377631     .42803     1.72   0.086    -.1046518    1.580178
     somecol |    .945057   .4524161     2.09   0.038     .0546472    1.835467
     college |   1.825737   .4633846     3.94   0.000     .9137394    2.737734
      female |  -.9026911   .2776765    -3.25   0.001    -1.449192   -.3561901
    age35_44 |  -.4560811   .4163007    -1.10   0.274    -1.275411    .3632492
    age45_59 |   .3901857   .4163743     0.94   0.349    -.4292895    1.209661
      age60p |  -.3134895   .4442036    -0.71   0.481    -1.187736    .5607571
    minority |  -1.817642   .3445003    -5.28   0.000     -2.49566   -1.139623
      income |   .1115623   .0362645     3.08   0.002     .0401894    .1829353
      employ |  -.4769254   .3131484    -1.52   0.129     -1.09324    .1393887
     married |  -.0134323   .2958083    -0.05   0.964    -.5956189    .5687543
       _cons |   2.512157   .6128275     4.10   0.000     1.306039    3.718276
-------------+----------------------------------------------------------------

-------------
-> group = 24 hours/

      Source |       SS       df       MS              Number of obs =     298
-------------+------------------------------           F( 12,   285) =    8.07
       Model |   725.49327    12  60.4577725           Prob > F      =  0.0000
    Residual |  2134.51009   285  7.48950907           R-squared     =  0.2537
-------------+------------------------------           Adj R-squared =  0.2222
       Total |  2860.00336   297  9.62964093           Root MSE      =  2.7367

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
     polint2 |    .475419   .1909526     2.49   0.013     .0995627    .8512753
      hsonly |   .3357658   .5086197     0.66   0.510    -.6653618    1.336893
     somecol |   2.267748   .5715951     3.97   0.000     1.142665    3.392831
     college |   2.019696   .5691813     3.55   0.000     .8993635    3.140028
      female |  -.3377782   .3270253    -1.03   0.303    -.9814695    .3059131
    age35_44 |   .4569692   .4750968     0.96   0.337    -.4781746    1.392113
    age45_59 |    .654652   .4615995     1.42   0.157    -.2539248    1.563229
      age60p |   1.033658   .5063817     2.04   0.042     .0369356    2.030381
    minority |  -1.918766   .4155551    -4.62   0.000    -2.736713    -1.10082
      income |    .125871   .0475464     2.65   0.009     .0322843    .2194576
      employ |  -.2020397   .3839506    -0.53   0.599    -.9577783    .5536988
     married |   .1399052   .3608965     0.39   0.699    -.5704555     .850266
       _cons |   2.276362   .7278692     3.13   0.002     .8436809    3.709044
-------------+----------------------------------------------------------------


.         bysort group: regress allknow polint hsonly somecol college female age35_44 age45_59 age60p minority income employ married

-------------
-> group = 60 second

      Source |       SS       df       MS              Number of obs =     312
-------------+------------------------------           F( 12,   299) =   12.66
       Model |  807.106571    12   67.258881           Prob > F      =  0.0000
    Residual |  1588.35176   299  5.31221325           R-squared     =  0.3369
-------------+------------------------------           Adj R-squared =  0.3103
       Total |  2395.45833   311  7.70243837           Root MSE      =  2.3048

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
      polint |   .7886965   .1453925     5.42   0.000     .5025744    1.074819
      hsonly |   .4902814   .3887471     1.26   0.208    -.2747455    1.255308
     somecol |   .7299423    .462764     1.58   0.116    -.1807448    1.640629
     college |   1.985143   .4260935     4.66   0.000     1.146621    2.823665
      female |  -.4254206   .2690791    -1.58   0.115    -.9549493    .1041081
    age35_44 |  -.2779145   .3913545    -0.71   0.478    -1.048073    .4922436
    age45_59 |  -.2710489   .3955144    -0.69   0.494    -1.049393    .5072956
      age60p |  -.7075221   .4266554    -1.66   0.098     -1.54715    .1321056
    minority |  -.7385482   .3418101    -2.16   0.032    -1.411206   -.0658899
      income |   .1761997   .0370563     4.75   0.000     .1032754     .249124
      employ |  -.7654826   .3280644    -2.33   0.020     -1.41109    -.119875
     married |  -.0441773   .2874241    -0.15   0.878    -.6098078    .5214532
       _cons |   1.578689   .5917454     2.67   0.008     .4141755    2.743202
-------------+----------------------------------------------------------------

-------------
-> group = 24 hours/

      Source |       SS       df       MS              Number of obs =     302
-------------+------------------------------           F( 12,   289) =    7.55
       Model |  618.217403    12   51.518117           Prob > F      =  0.0000
    Residual |   1972.5773   289  6.82552698           R-squared     =  0.2386
-------------+------------------------------           Adj R-squared =  0.2070
       Total |   2590.7947   301  8.60729137           Root MSE      =  2.6126

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
      polint |   .5654611   .1708657     3.31   0.001     .2291621    .9017601
      hsonly |   .5457598   .4645265     1.17   0.241    -.3685244    1.460044
     somecol |   .7570177     .49876     1.52   0.130    -.2246449     1.73868
     college |   1.791576   .4795383     3.74   0.000     .8477452    2.735406
      female |  -.4516611   .3170073    -1.42   0.155    -1.075597    .1722747
    age35_44 |   .2574472   .4627128     0.56   0.578     -.653267    1.168161
    age45_59 |   .4848681   .4589595     1.06   0.292     -.418459    1.388195
      age60p |   1.497022    .500587     2.99   0.003     .5117633     2.48228
    minority |  -1.086082   .3680826    -2.95   0.003    -1.810545   -.3616195
      income |   .1010607   .0435432     2.32   0.021     .0153586    .1867628
      employ |    .023515   .3802367     0.06   0.951    -.7248694    .7718993
     married |   .3201425   .3302206     0.97   0.333    -.3297998    .9700848
       _cons |   1.987291    .747111     2.66   0.008     .5168221     3.45776
-------------+----------------------------------------------------------------

-------------
-> group = 60 second

      Source |       SS       df       MS              Number of obs =     306
-------------+------------------------------           F( 12,   293) =   14.86
       Model |  1006.71698    12  83.8930816           Prob > F      =  0.0000
    Residual |   1654.6425   293  5.64724402           R-squared     =  0.3783
-------------+------------------------------           Adj R-squared =  0.3528
       Total |  2661.35948   305  8.72576878           Root MSE      =  2.3764

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
      polint |   .8933872   .1617756     5.52   0.000     .5749978    1.211777
      hsonly |   .6867203   .4258121     1.61   0.108    -.1513177    1.524758
     somecol |   .9101164   .4515538     2.02   0.045     .0214163    1.798816
     college |   1.782439   .4619934     3.86   0.000     .8731923    2.691685
      female |  -.8920996   .2776428    -3.21   0.001    -1.438526   -.3456726
    age35_44 |   -.407404   .4142344    -0.98   0.326    -1.222656     .407848
    age45_59 |   .3959347   .4165318     0.95   0.343    -.4238389    1.215708
      age60p |   -.319916   .4443684    -0.72   0.472    -1.194474    .5546426
    minority |  -1.838298   .3441669    -5.34   0.000     -2.51565   -1.160945
      income |   .1127261   .0362662     3.11   0.002     .0413508    .1841014
      employ |  -.5044632   .3123321    -1.62   0.107    -1.119162    .1102356
     married |  -.0050298   .2958481    -0.02   0.986    -.5872866     .577227
       _cons |   2.574752   .6105739     4.22   0.000     1.373085    3.776418
-------------+----------------------------------------------------------------

-------------
-> group = 24 hours/

      Source |       SS       df       MS              Number of obs =     300
-------------+------------------------------           F( 12,   287) =    8.17
       Model |   730.70321    12  60.8919342           Prob > F      =  0.0000
    Residual |  2138.96346   287  7.45283434           R-squared     =  0.2546
-------------+------------------------------           Adj R-squared =  0.2235
       Total |  2869.66667   299  9.59754738           Root MSE      =    2.73

-------------+----------------------------------------------------------------
     allknow |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
      polint |   .4623511   .1884342     2.45   0.015     .0914629    .8332393
      hsonly |   .3654407   .5051237     0.72   0.470    -.6287761    1.359658
     somecol |   2.273151   .5700623     3.99   0.000     1.151118    3.395185
     college |   2.037723   .5671813     3.59   0.000     .9213603    3.154085
      female |  -.3554883   .3251963    -1.09   0.275    -.9955606     .284584
    age35_44 |   .4435212   .4716837     0.94   0.348    -.4848768    1.371919
    age45_59 |   .6371003   .4598279     1.39   0.167    -.2679625    1.542163
      age60p |   1.002991   .5033874     1.99   0.047     .0121915     1.99379
    minority |  -1.884824   .4120995    -4.57   0.000    -2.695945   -1.073704
      income |   .1220639   .0471726     2.59   0.010     .0292158     .214912
      employ |  -.2213067   .3819702    -0.58   0.563    -.9731249    .5305114
     married |   .1431416   .3597317     0.40   0.691    -.5649054    .8511886
       _cons |   2.356771    .718577     3.28   0.001     .9424221    3.771121
-------------+----------------------------------------------------------------


.
. *2.5.10 Manipulation checks
.
.
.         *** main experimental effects ON LENGTH of interview
.
.                 * GRAPH of interview length with distributional measures
.                         recode int_dur 0/4.99=0 5/200=1 201/100000=2, gen(int_dur1)
(1203 differences between int_dur and int_dur1)

.                         gen int_dur2=int_dur
(17 missing values generated)

.                         recode int_dur2 61/200=62 201/100000=64
(int_dur2: 72 changes made)

.                         gen int_dur3=ln(int_dur)
(17 missing values generated)

.                         twoway hist int_dur2, by(group) start(0) width(1) frac

.                         tab int_dur1 group, nof col

 RECODE of |
   int_dur |
   (survey |
 length in |              data-only: group
  minutes) | 60 second  24 hours/  60 second  24 hours/ |     Total
-----------+--------------------------------------------+----------
         0 |      2.27       1.69       0.99       0.34 |      1.33
         1 |     95.15      93.22      95.36      91.58 |     93.85
         2 |      2.59       5.08       3.64       8.08 |      4.82
-----------+--------------------------------------------+----------
     Total |    100.00     100.00     100.00     100.00 |    100.00


.
.
.                 * Main effects on LENGTH
.                         table group if int_dur<61, c(mean int_dur) format(%4.1f)

---------------------------------+--------------
                data-only: group | mean(int_dur)
---------------------------------+--------------
               60 seconds/no pay |          11.9
                 24 hours/no pay |          14.6
60 seconds/$1 per correct answer |          12.8
  24 hours/$1 per correct answer |          16.6
---------------------------------+--------------

.                         table group, c(p25 int_dur median int_dur p75 int_dur) format(%4.2f)

---------------------------------+-----------------------------------------
                data-only: group | p25(int_dur)  med(int_dur)  p75(int_dur)
---------------------------------+-----------------------------------------
               60 seconds/no pay |         8.25         11.68         14.55
                 24 hours/no pay |         9.68         12.85         18.40
60 seconds/$1 per correct answer |         9.07         12.09         15.32
  24 hours/$1 per correct answer |        10.83         15.00         22.72
---------------------------------+-----------------------------------------

.
.                         anova int_dur time pay time*pay if int_dur<61

                           Number of obs =    1131     R-squared     =  0.0556
                           Root MSE      =  7.3734     Adj R-squared =  0.0531

                  Source |  Partial SS    df       MS           F     Prob > F
              -----------+----------------------------------------------------
                   Model |  3606.18743     3  1202.06248      22.11     0.0000
                         |
                    time |   2946.1092     1   2946.1092      54.19     0.0000
                     pay |   622.89965     1   622.89965      11.46     0.0007
                time*pay |  79.1656872     1  79.1656872       1.46     0.2278
                         |
                Residual |  61271.7189  1127  54.3670975
              -----------+----------------------------------------------------
                   Total |  64877.9063  1130  57.4140764

.                         anova int_dur2 time pay time*pay

                           Number of obs =    1203     R-squared     =  0.0549
                           Root MSE      = 13.5362     Adj R-squared =  0.0526

                  Source |  Partial SS    df       MS           F     Prob > F
              -----------+----------------------------------------------------
                   Model |  12771.7849     3  4257.26162      23.23     0.0000
                         |
                    time |  9858.87341     1  9858.87341      53.81     0.0000
                     pay |   2443.0883     1   2443.0883      13.33     0.0003
                time*pay |  445.279096     1  445.279096       2.43     0.1193
                         |
                Residual |  219689.928  1199   183.22763
              -----------+----------------------------------------------------
                   Total |  232461.713  1202  193.395768

.                         anova int_dur3 time pay time*pay

                           Number of obs =    1203     R-squared     =  0.0328
                           Root MSE      =  1.2401     Adj R-squared =  0.0304

                  Source |  Partial SS    df       MS           F     Prob > F
              -----------+----------------------------------------------------
                   Model |  62.4754571     3  20.8251524      13.54     0.0000
                         |
                    time |  46.9981967     1  46.9981967      30.56     0.0000
                     pay |  14.2345914     1  14.2345914       9.26     0.0024
                time*pay |  1.02781937     1  1.02781937       0.67     0.4138
                         |
                Residual |  1843.87104  1199  1.53784073
              -----------+----------------------------------------------------
                   Total |   1906.3465  1202  1.58597878

.                         regress int_dur2 time pay

      Source |       SS       df       MS              Number of obs =    1203
-------------+------------------------------           F(  2,  1200) =   33.60
       Model |  12326.5058     2  6163.25288           Prob > F      =  0.0000
    Residual |  220135.207  1200  183.446006           R-squared     =  0.0530
-------------+------------------------------           Adj R-squared =  0.0514
       Total |  232461.713  1202  193.395768           Root MSE      =  13.544

-------------+----------------------------------------------------------------
    int_dur2 |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
        time |   5.721608   .7811194     7.32   0.000     4.189096     7.25412
         pay |   2.831452   .7810287     3.63   0.000     1.299118    4.363785
       _cons |   12.61323   .6702732    18.82   0.000     11.29819    13.92827
-------------+----------------------------------------------------------------

.
.
.                 * Knowledge by absolute and relative LENGTH of interview
.
.                    * absolute
.                         gen int_dur_temp = int_dur
(17 missing values generated)

.                         replace int_dur_temp=10000 if incomp==1
(17 real changes made)

.                         recode int_dur_temp 0/8.66=0 8.66/11.39=1 11.39/14.1=2 14.1/19.84=3 19.84/100000=4, gen(int_dur5)
(1220 differences between int_dur_temp and int_dur5)

.                         table int_dur5 group , c(mean allknow) format(%4.2f)

----------+---------------------------------------------------------------------------------------
RECODE of |
int_dur_t |                                    data-only: group
emp       |    60 seconds/no pay       24 hours/no pay  60 seconds/$1 per co  24 hours/$1 per corr
----------+---------------------------------------------------------------------------------------
        0 |                 5.25                  4.82                  4.98                  5.47
        1 |                 4.73                  5.53                  5.45                  5.12
        2 |                 4.56                  5.59                  5.20                  5.33
        3 |                 3.97                  5.73                  4.76                  5.43
        4 |                 3.03                  5.07                  4.65                  6.22
----------+---------------------------------------------------------------------------------------

.
.                    * relative
.                         table group, c(p20 int_dur_temp p40 int_dur_temp p60 int_dur_temp p80 int_dur_temp) format(%4.2f)

---------------------------------+-----------------------------------------------------------
                data-only: group | p20(int_du~p)  p40(int_du~p)  p60(int_du~p)  p80(int_du~p)
---------------------------------+-----------------------------------------------------------
               60 seconds/no pay |          7.65           9.68          13.02          15.68
                 24 hours/no pay |          9.27          11.90          14.57          21.25
60 seconds/$1 per correct answer |          8.60          10.78          13.30          16.60
  24 hours/$1 per correct answer |         10.13          12.91          17.55          30.17
---------------------------------+-----------------------------------------------------------

.                         gen int_dur5r=1 if group==1 & int_dur_temp<7.65
(1158 missing values generated)

.                         replace int_dur5r=1 if group==2 & int_dur_temp<9.27
(61 real changes made)

.                         replace int_dur5r=1 if group==3 & int_dur_temp<8.6
(60 real changes made)

.                         replace int_dur5r=1 if group==4 & int_dur_temp<10.13
(60 real changes made)

.                         replace int_dur5r=2 if group==1 & int_dur_temp>=7.65 & int_dur_temp<9.68
(62 real changes made)

.                         replace int_dur5r=2 if group==2 & int_dur_temp>=9.27 & int_dur_temp<11.9
(60 real changes made)

.                         replace int_dur5r=2 if group==3 & int_dur_temp>=8.6 & int_dur_temp<10.78
(62 real changes made)

.                         replace int_dur5r=2 if group==4 & int_dur_temp>=10.13 & int_dur_temp<12.91
(60 real changes made)

.                         replace int_dur5r=3 if group==1 & int_dur_temp<13.02 & int_dur_temp>=9.68
(64 real changes made)

.                         replace int_dur5r=3 if group==2 & int_dur_temp<14.57 & int_dur_temp>=11.9
(61 real changes made)

.                         replace int_dur5r=3 if group==3 & int_dur_temp<13.3 & int_dur_temp>=10.78
(61 real changes made)

.                         replace int_dur5r=3 if group==4 & int_dur_temp<17.55 & int_dur_temp>=12.91
(60 real changes made)

.                         replace int_dur5r=4 if group==1 & int_dur_temp>=13.02 & int_dur_temp<15.68
(61 real changes made)

.                         replace int_dur5r=4 if group==2 & int_dur_temp>=14.57 & int_dur_temp<21.25
(58 real changes made)

.                         replace int_dur5r=4 if group==3 & int_dur_temp>=13.3 & int_dur_temp<16.6
(61 real changes made)

.                         replace int_dur5r=4 if group==4 & int_dur_temp>=17.55 & int_dur_temp<30.17
(60 real changes made)

.                         replace int_dur5r=5 if group==1 & int_dur_temp<100000 & int_dur_temp>=15.68
(63 real changes made)

.                         replace int_dur5r=5 if group==2 & int_dur_temp<100000 & int_dur_temp>=21.25
(62 real changes made)

.                         replace int_dur5r=5 if group==3 & int_dur_temp<100000 & int_dur_temp>=16.6
(62 real changes made)

.                         replace int_dur5r=5 if group==4 & int_dur_temp<100000 & int_dur_temp>=30.17
(60 real changes made)

.                         table int_dur5r group , c(mean allknow) format(%4.2f)

----------+---------------------------------------------------------------------------------------
          |                                    data-only: group
int_dur5r |    60 seconds/no pay       24 hours/no pay  60 seconds/$1 per co  24 hours/$1 per corr
----------+---------------------------------------------------------------------------------------
        1 |                 5.32                  4.87                  5.03                  5.62
        2 |                 4.82                  5.45                  5.27                  4.78
        3 |                 5.00                  5.74                  5.59                  5.57
        4 |                 4.11                  5.60                  4.70                  5.97
        5 |                 3.44                  5.11                  4.63                  6.23
----------+---------------------------------------------------------------------------------------

.
.
end of do-file

. log close
       log:  M:\PriorLupia\Submit\Prior Lupia AJPS 08.smcl
  log type:  smcl
 closed on:  10 Jun 2009, 15:42:05
-------------