Variance and Course Completion Time

Case Problem Air Force Training Program
An Air Force introductory course in electronics uses a personalized system of instruction whereby each student views a videotaped lecture and then is given a programmed instruction text. The students work independently with the text until they have completed the training and passed a test. Of concern is the varying pace at which the students complete this portion of their training program. Some students are able to cover the programmed instruction text relatively quickly, whereas other students work much longer with the text and require additional time to complete the course. The fast students wait until the slow students complete the introductory course before the entire group proceeds together with other aspects of their training.
A proposed alternative system involves use of computer-assisted instruction. In this method, all students view the same videotaped lecture and then each is assigned to a computer terminal for further instruction. The computer guides the student, working independently, through the self-training portion of the course. To compare the proposed and current methods of instruction, an entering class of 122 students was assigned randomly to one of the two methods. One group of 61 students used the current programmed-text method and the other group of 61 students used the proposed computer-assisted method. The time in hours was recorded for each student in the study. The following date are provided in the date set training:

Course Completion Time(hours) for Current Training Method
76
76
77
74
76
74
74
77
72
78
73
78
75
80
79
72
69
79
72
70
70
81
76
78
72
82
72
73
71
70
77
78
73
79
82
65
77
79
73
76
81
69
75
75
77
79
76
78
76
76
73
77
84
74
74
69
79
66
70
74
72

Course Completion Time(hours) for Proposed Computer-Assisted Method
74
75
77
78
74
80
73
73
78
76
76
74
77
69
76
75
72
75
72
76