SI 544 Introduction to Statistics and Data Analysis


SI 544 home

Readings, assignments, etc. will be posted to the course ctools website

problem sets

software tools for the class

Lada Adamic



Fall 2010:

Lectures will be
Tuesdays and Thursdays
from 8:30 to 10:00 am.
Location NQ1255

Office hours:
TuTh 10:00-10:30 and Fri 2-3pm in NQ4360

PS2 Probability



1. 5 pregnant women
5 pregnant women are sitting around a table.

A (20pts). What is the probability that all of them will have boys?

B (20pts). What is the probability that one will have a girl, while the rest have boys?

2. UofM graduation rates
By looking at statistics for UofM freshman enrollment by ethnicity, you know that
the probability of a freshman being black is 0.08 (8%), asian is 0.13, hispanic is 0.06, and white/other is 0.73. You also know that the 4-year graduation rates for those groups are 0.51 (black), 0.76 (asian), 0.67 (hispanic), and 0.75 (white/other).

A (20 pts). Draw a probability tree with the first branching corresponding to ethnicity, and the second corresponding to whether the student graduated in four years or not.

B (20 pts). What is the probability that a student does not graduate in 4 years?

C (20 pts). What is the probability that a student who graduated in 4 years is black? That is, given that he/she graduated in 4 years, what is the probability that he/she is black?