An investigator for the state police wants to determine the effectiveness of three different defensive driving training programs to see if there are gender differences. Five subjects of each gender who recently received speeding tickets are assigned to each program. At the end of the program, each is given a written test on his or her knowledge of defensive driving. The scores (out of 100) are given next.

(a) The scores are approximately normally distributed. Verify the requirement of equal population variances.
(b) Determine whether there is significant interaction between program and gender.
(c) If there is no significant interaction, determine whether there is significant difference in the means for the three programs.
(d) Draw an interaction plot of the data to support the results of parts (b) and (c).
(e) If there is significant difference in the means for the three programs, use Tukey's test to determine which pairwise means differ using a familywise error rate of a = 0.05.