State the critical values for a one-sample t test given the following conditions:
(a) Two-tailed test, α = .05, n = 12
(b) One-tailed test, lower tail critical, α = .01, df = 15
(c) Two-tailed test, α = .01, df = 26
(d) One-tailed test, upper tail critical, α = .05, n = 30