12. Claim: m 1 7 m 2 ; a = 0.01. Assume s 12 s 22 . Sample statistics: x 1 = 52, s 1 = 4.8, n 1 = 32 and x 2 = 50, s 2 = 1.2, n 2 = 40

In Exercises 912, test the claim about the difference between two population means m 1 and m 2 at the level of significance a . Assume the samples are random and independent, and the populations are normally distributed.