Fifteen trainees in a technical program are randomly assigned to three different types of

instructional approaches, all of which are concerned with developing a specified level of skill

in computer-assisted design. The achievement test scores at the conclusion of the

instructional unit are reported in Table along with the mean performance score associated

with each instructional approach. Use the analysis of variance procedure to test the null

hypothesis that the three-sample means were obtained from the same population, using the

5 percent level of significance for the test.

A1 86 79 81 70 84| Total Score -400 Mean -80

A2 90 76 88 82 89| Total- 425 Mean -85

A3 82 68 73 71 81| Total-375 Mean- 75