The Perry Preschool Project discussed in Exercises 10.39-10.41 found that 8 of the 58 students who attended preschool had at least one felony arrest by age 40 and that 31 of the 65 students who did not attend preschool had at least one felony arrest (Schweinhart et al. 2005).
a. Compare the percentages descriptively. What does this comparison suggest?
b. Create a two-way table from the data and do a chi-square test on it, using a significance level of 0.05. Test the hypothesis that preschool attendance is associated with being arrested.
c. Do a two-proportion z-test. Your alternative hypothesis should be that preschool attendance lowers the chances of arrest.
d. What advantage does the two-proportion z-test have over the chi square test?