72. For the data of Exercise 69 now consider testing the hypothesis of equal population variances.

a. Carry out a two-tailed test using the method of Section 10.5. Recall that this method requires the data to be normal, and the method is sensitive to departures from normality. Check the data for normality to see if the F test is justi ed.

b. Carry out a two-tailed permutation test for the hypothesis of equal population variances (or standard deviations). Why does it not matter whether you use variances or standard deviations?

c. Compare the two results and summarize your conclusions.