14.12 Determine the critical value that would be used to test the null hypothesis for the following situations using the classical approach and the sign test:

a. Ho: P()  0.5 vs. Ha: P()  0.5, with n  18 and   0.05

b. Ho: P()  0.5 vs. Ha: P()  0.5, with n  78 and   0.05

c. Ho: P()  0.5 vs. Ha: P()  0.5, with n  38 and   0.05

d. Ho: P()  0.5 vs. Ha: P()  0.5, with n  148 and   0.05