The purpose of this study was to compare experimentally the relative effectiveness of two instructional media--a computer-based display unit and a programed-text booklet--for presenting selected instructional units of a common program for teaching FORTRAN IV. In conducting the study a common program for teaching FORTRAN was prepared and presented by the media being tested to 49 University of Missouri students who took Computer Science 103 during the Fall semester of 1969. Several measurements were obtained for each student including programing aptitude as measured by a Programmer Aptitude Test, and the number of cognitive errors made while working with the medium. Based on these measurements, it was found that students taught by programed-text booklets made significantly fewer errors when working with the media than did students taught by computer-based display units. However, it was concluded that neither of the two media is superior to the other when they are used for presenting programed instruction to Computer Science 103 students in regard to knowledge of language rules, ability to solve programing problems, and attitude. (Author)