10.2 Find the critical value(s) of t that specify the rejection region in these situations:

a. A two-tailed test with a = 0.01 and 12 df

b. A right-tailed test with a 0.05 and 16 df

c. A two-tailed test with a = 0.05 and 25 df

d. A left-tailed test with a = 0.01 and 7 df