Question: Determine the critical region and critical values for z that would be used to test the null hypothesis at the given level of significance, as described in each of the following:

(A) Null Hypothesis (Ho): u (mean) Less than & equal to 20 and Alternative Hypothesis (Ha): u (mean)>20, α = 0.05
(B) Null Hypothesis (Ho): u (mean) = 25 and Alternative Hypothesis (Ha): u (mean)=(with a slash thru the equal sign) 25, α = 0.10
(C) Null Hypothesis (Ho): u (mean) > & equal to 18 and Alternative Hypothesis (Ha): u (mean)<18, α = 0.01