Find the rejection region?

Question

Find the rejection regions for the following tests when sigma^2 is unknown
in terms of t:
(a) A test of H0 : µ = 0 versus H1 : µ not equal to 0 with alpha = 0.05 and n = 9.
(b) A test of H0 : µ = 0 versus H1 : µ > 0 with alpha = 0.01 and n = 14.
(c) A test of H0 : µ = 0 versus H1 : µ < 0 with alpha = 0.05 and n = 12.

Answer 1

a) a 2-sided test. t-crit=2.262 reject h-naught if |t|>t-crit
b) a 1-sided test t-crit=2.624 reject h-naught if t>t-crit
c) a 1-sided test t-crit=1.782 reject h-naught if t<-t-crit