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.
Course Completion Times (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 Times (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 72 77
73 77 69 77 75 76 74 77 75 78 72
77 78 78 76 75 76 76 75 76 80 77
76 75 73 77 77 77 79 75 75 72 82
76 76 74 72 78 71
1. What is the 95% confidence interval for the mean hours to completion for the Current Training Method?
2. What is the 95% confidence interval for the mean hours to completion for the Proposed Computer-Assisted Method?
3. What is the sample standard deviation for the hours to completion for the Current Training Method?
4. What is the sample standard deviation for the hours to completion for the Proposed Computer-Assisted Method?