Determine the critical region and critical value(s) that would be used in the classical approach to test the following null hypotheses:

a. Ho :   10, Ha:   10 (  0.05, n  15)

b. Ho :   37.2, Ha:  37.2

(  0.01, n  25)

c. Ho: 20.5, Ha: 20.5 (  0.05, n  18)

d. Ho :   32.0, Ha:   32.0

(  0.01, n  42)