14.23 An organization offers a program designed to increase the level of comprehension achieved by students when reading technical material quickly. Each member of a random sample of 10 students was given 30 minutes to read an article. A test of the level of comprehension achieved was then administered. This process was repeated after these students had completed the program. The accompanying table shows comprehension scores before and after completion of the program.

Use the sign test to test the null hypothesis that for this population there is no overall improvement in comprehension levels following completion of the program.

Student Before After A 79 87 B 57 68 C 87 83 D 85 85 E 77 89 F 60 67 G 92 106 H 83 85 I 73 70 J 77 85