Consider the college graduation data introduced in Section 9.7.
a. Create a plot and compare the survival experiences to investigate whether there are differences in the time required to obtain a bachelor’s degree by gender. What do you observe about the survival probabilities of the genders?
b. Conduct the log- rank test and the Wilcoxon test to compare the survival curves of the two genders. Interpret the results.
c. (R software is suggested for this problem.) Plot and examine the estimator of the cumulative hazard function. Discuss the changes in the rate of change of H^(t) NA as each of the following time periods passes, and discuss corresponding changes in the hazard rate of graduation as college students move from one time interval to another.
• 0 – 3.75 years
• 3.75 – 4.75 years
• 74.75 years