94 Specify the appropriate rejection region for testing against H0: s1 2 = s2 2 in each of the following situations:

a. Ha: s1 2 7 s2 2 ; a = .05, n1 = 25, n2 = 20

b. Ha: s1 2 6 s2 2 ; a = .05, n1 = 10, n2 = 15

c. Ha: s1 2  s2 2 ; a = .10, n1 = 21, n2 = 31

d. Ha: s1 2 6 s2 2 ; a = .01, n1 = 31, n2 = 41

e. Ha: s1 2  s2 2 ; a = .05, n1 = 7, n2 = 16