As part of an industrial training program, some trainees are instructed by Method A, which is straight computer-based instruction, and some are instructed by Method B, which also involves the personal attention of an instructor. If random samples of size 10 are taken from large groups of trainees instructed by each of these two methods, and the scores which they obtained in an approximate achievements test are
Method A: 71, 75, 65, 69, 73, 66, 68, 71, 74, 68
Method B: 72, 77, 84, 78, 69, 70, 77, 73, 65, 75
use the 0.05 level of significance to test the claim that Method B is more effective. Assume that the populations sampled can be approximated closely with normal distributions having the same variance.