We have data for two groups: college juniors represented by the subscript 1 and college seniors represented by the subscript 2. do a two-sample test for equality of means assuming unequal variances. minitab will be of great assistance. when exam-time rolls around, make certain that you are able to calculate tcalc by hand. (a-1) comparison of gpa for randomly chosen college juniors and seniors: x¯1x¯1 = 3.05, s1 = .20, n1 = 15, x¯2x¯2 = 3.25, s2 = .30, n2 = 15, α = .025, left-tailed test.