Determine the critical region and the critical values used to test the following null hypotheses:
a. Ho: μ = 55 (≥), Ha: μ < 55, α = 0.02
b. Ho: μ = −86 (≥), Ha: μ < −86, α = 0.01
c. Ho: μ = 107, Ha: μ ≠ 107, α = 0.05
d. Ho: μ = 17.4 (≤), Ha: μ > 17.4, α = 0.10