Two independent random samples were selected from normally distributed populations with means and variances LO3 1m1, s21 2 and 1m2, s22 2, respectively. The sample sizes, means, and variances are shown in the following table.

Sample 1 Sample 2 n1 = 15 n2 = 20 x1 = 123 x2 = 116 s1 2

= 15.65 s2 2

= 60.05

*a. Test H0: s1 2

= s2 2 against Ha: s1 2  s2 2 . Use a = .05.

b. Would you be willing to use a t-test to test the null hypothesis H0: 1m1 - m22 = 0 against the alternative hypothesis Ha: 1m1 - m22  0? Why?