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 data are provided in the data set Training.

Managerial Report We discuss interval estimation and hypothesis testing on the difference between population means in Chapter 10.

1. Use appropriate descriptive statistics to summarize the training time data for each method. What similarities or differences do you observe from the sample data?

2. Conduct a hypothesis test on the difference between the population means for the two methods. Discuss your findings.

3. Compute the standard deviation and variance for each training method. Conduct a hypothesis test about the equality of population variances for the two training methods. Discuss your findings.

4. What conclusion can you reach about any differences between the two methods? What is your recommendation? Explain.

Current	Proposed
76	74
76	74
77	77
74	78
76	74
74	80
74	73
77	73
72	78
78	76
73	76
78	74
75	77
80	69
79	76
72	75
69	72
79	75
62	72
70	76
70	72
81	77
76	73
78	77
72	69
82	77
72	75
73	76
71	74
68	77
77	75
78	78
73	72
79	77
82	78
65	78
77	76
79	75
73	76
76	76
81	75
69	76
75	80
77	75
76	77
75	79
73	76
77	78
77	76
77	76
79	73
75	77
75	74
72	74
82	74
76	69
76	79
74	66
72	70
78	74
71	72