Using Table G, find the critical value(s) for each. Show the critical and noncritical regions, and state the appropriate null and alternative hypotheses. Use σ² = 225.

a. α = 0.01, n = 17, right-tailed
b. α = 0.025, n = 20, left-tailed
c. α = 0.01, n = 13, two-tailed
d. α = 0.025, n = 29, left-tailed