Which samples show unequal variances? Use = .05 in all tests. Show the critical values and degrees of freedom clearly and illustrate the decision

Which samples show unequal variances? Use α = .05 in all tests. Show the critical values and degrees of freedom clearly and illustrate the decision rule.
a. s1 = 5.1, n1 5 11, s2 = 3.2, n2 = 8, two-tailed test
b. s1 = 221, n1 5 8, s2 = 445, n2 = 8, left-tailed test
c. s1 = 67, n1 5 10, s2 = 15, n2 = 13, right-tailed test