* ******************************************************************
*  SPSS EXAMPLE 2: 
*  LINEAR REGRESSION AND DIAGNOSTICS
* DUMMY VARIABLE REGRESSION AND DIAGNOSTICS
* *****************************************************************.
GET FILE="e:\510\2006\werner.sav".

COMPUTE bodymass = (weight/2.2026)/(height*.0254)**2 .
EXECUTE .

*-----------------------------------------------------------------------------DESCRIPTIVES.
DESCRIPTIVES
  VARIABLES=AGE HEIGHT WEIGHT PILL CHOL ALB CALCIUM ACID PAIR logwt hichol bodymass
  /STATISTICS=MEAN STDDEV MIN MAX .

*-------------------------------------------------------------------------------CORRELATION.
CORRELATIONS
  /VARIABLES=chol age 
  /PRINT=TWOTAIL NOSIG
  /MISSING=PAIRWISE .

*-------------------------------------------------------------------------------SCATTER PLOT.
GRAPH
  /SCATTERPLOT(BIVAR)=age  WITH chol 
  /MISSING=LISTWISE .


*-------------------------------------------------------------------------------SIMPLE REGRESSION.
REGRESSION
  /MISSING LISTWISE
  /STATISTICS COEFF OUTS R ANOVA
  /CRITERIA=PIN(.05) POUT(.10)
  /NOORIGIN
  /DEPENDENT CHOL
  /METHOD=ENTER AGE
  /RESIDUALS HIST(ZRESID) NORM(ZRESID)
  /SAVE PRED RESID SDRESID .

*-------------------------------------------------------------------------------SCATTERPLOT of RESIDUALS (Y) BY PREDICTED (X) .
GRAPH
  /SCATTERPLOT(BIVAR)=PRE_1 WITH SDR_1
  /MISSING=LISTWISE .

*-------------------------------------------------------------------------------CHECK NORMALITY OF RESIDUALS
                                                                                (Analyze...Descriptive Statisics...Explore).
EXAMINE
  VARIABLES=SDR_1
  /PLOT BOXPLOT STEMLEAF NPPLOT
  /COMPARE GROUP
  /STATISTICS DESCRIPTIVES
  /CINTERVAL 95
  /MISSING LISTWISE
  /NOTOTAL.

*------------------------------------------------------------------------------CREATE AGEGROUP (SAME CATEGORIES AS SAS ANAL).
RECODE
  age
  (Lowest thru 25=1)  (25 thru 32=2)  (32 thru 42=3) (42 thru Highest=4)  INTO  AGEGRP .
EXECUTE .

VALUE LABELS
          AGEGROUP (1) <= 25 (2) 26-32 (3) 32-42(4) >42.

*------------------------------------------------------------------------------CREATE AGE DUMMY VARIABLES.

do if not  missing(AGEGRP).
COMPUTE AGEDUM1 = (AGEGRP=1).
COMPUTE AGEDUM2 = (AGEGRP=2).
COMPUTE AGEDUM3 = (AGEGRP=3).
COMPUTE AGEDUM4 = (AGEGRP=4).
end if.
EXECUTE .

*------------------------------------------------------------------------------BOXPLOTS OF CHOL BY AGEGROUP.
EXAMINE
  VARIABLES=CHOL BY AGEGRP /PLOT=BOXPLOT/STATISTICS=NONE/NOTOTAL.

*------------------------------------------------------------------------------DESCRIPTIVES FOR CHOL BY AGEGROUP
                                                         (Analyze...Compare Means...Means...Agegroup is the Factor).
MEANS
  TABLES=CHOL  BY AGEGRP
  /CELLS MEAN COUNT STDDEV MIN MAX MEDIAN .


*---------------------------------------------DUMMY VARIABLE REGRESSION.

REGRESSION
  /MISSING LISTWISE
  /STATISTICS COEFF OUTS R ANOVA
  /CRITERIA=PIN(.05) POUT(.10)
  /NOORIGIN
  /DEPENDENT CHOL
  /METHOD=ENTER AGEDUM2 AGEDUM3 AGEDUM4
  /RESIDUALS HIST(ZRESID) NORM(ZRESID)
  /SAVE PRED RESID SDRESID .

*---------------------------------------------SCATTERPLOT OF STUDENTIZED RESIDUALS VS PREDICTED VALUES.
GRAPH
  /SCATTERPLOT(BIVAR)=PRE_2 WITH SDR_2
  /MISSING=LISTWISE .


 
EXAMINE
  VARIABLES=SDR_1
  /PLOT BOXPLOT STEMLEAF HISTOGRAM NPPLOT
  /COMPARE GROUP
  /STATISTICS NONE
  /CINTERVAL 95
  /MISSING LISTWISE
  /NOTOTAL.

EXAMINE
  VARIABLES=CHOL BY AGEGRP /PLOT=BOXPLOT/STATISTICS=NONE/NOTOTAL.
MEANS
  TABLES=CHOL  BY AGEGRP
  /CELLS MEAN COUNT STDDEV MIN MAX  .