State the critical values for a two-independent-sample t test given the following conditions: 1. Two-tailed test, = .01, total df = 26 2. One-tailed

State the critical values for a two-independent-sample t test given the following conditions:

1. Two-tailed test, α = .01, total df = 26 2. One-tailed test, lower-tail critical, α = .01, df = 15 for each group 3. Two-tailed test, α = .05, n = 12 in each group 4. One-tailed test, upper-tail critical, α = .05, n for both groups combined is 30