Abstract
The major purpose of this study was to explore an effective method for large group instruction for students majoring in general engineerings, by means of closed-circuit television, large transparencies, and video tapes. This report, the second part of a three-year project, mainly deals with the analysis of students' test results and their attitudes toward audio-visual techniques used in the course of Fluid Mechanics. A total of 465 freshman students were enrolled in 1966, and divided into two classes, from which 268 were selected as final subjects. The investigation compared the attainments of 92 students instructed by CCTV - though video taped programs were used in the last two of the ten chapters (TV class), with those of 176 - the rest of the total - instructed with the use of an overhead projector (OHP class). The difference in number between the two classes was caused merely by enrollments. Both classes were taught by the same professor. The course consisted of one period (90 minutes) per week over a semester of 15 weeks. To compare the relative effectiveness of OHP and TV teaching, multiple-choice test items were developed from the view point of basic subject matter understanding (20 items for the Before Test and 30 for the After Test). The indexes of test reliability and item validity were calculated. A questionnaire was also filled out by each student as part of the final examination. Findings of the study included the following: 1) With respect to the understanding of factual information, as a whole, OHP and TV teaching appeared to be equally effective. 2) Partial use of video tapes in teaching showed promising consideration as a medium for large group instruction. 3) Audio-visual techniques used in this study were accepted favorable by a majority of students in the two classes (more than 70%). However, there was a statistically significant difference in attitude toward A-V teaching (students using OHP scored higher than those using TV). 4) In the TV classes, there appeared to be some quadratic correlation (not linear) between the after test scores on students' achievements and their attitudes toward class participation and A-V method, whereas OHP class showed no such relation. That is, as for interest in the A-V method and in class participation, based on after test scores, the lowest 27% and the highest 27% on the average, showed a lesser degree of interest than the middle 46%. These comparisons of achievement scores and their attitudes toward teaching showed great variation, apparently due more to the quality of students than to the types of media used. Detailed analysis and discussions, therefore, needs further investigation.
