512 Chapter 14 Repeated-Measures Designs
14.24 In the data file Stress.dat, available on the Web site, are data on the stress level reported by can-
cer patients and their spouses at two different times—shortly after the diagnosis and 3 months
later. The data are also distinguished by the gender of the respondent. As usual, a “.” indicates
each missing data point. See description in Appendix: Computer Data Sets, p. 692.
a. Use any statistical package to run a repeated-measures analysis of variance with
Gender and Role (patient versus spouse) as between-subject variables and Time as the
repeated measure.
b. Have the program print out cell means, and plot these means as an aid in interpretation.
c. There is a significant three-way interaction in this analysis. Interpret it along with the
main effects.
14.25 Everitt reported data on a study of three treatments for anorexia in young girls. One treat-
ment was cognitive behavior therapy, a second was a control condition with no therapy, and
a third was a family therapy condition. The data follow:
Group Pretest Posttest Gain
1 80.5 82.2 1.7
1 84.9 85.6 .7
1 81.5 81.4 2 .1
1 82.6 81.9 2 .7
1 79.9 76.4 2 3.5
1 88.7 103.6 14.9
1 94.9 98.4 3.5
1 76.3 93.4 17.1
1 81.0 73.4 2 7.6
1 80.5 82.1 1.6
1 85.0 96.7 11.7
1 89.2 95.3 6.1
1 81.3 82.4 1.1
1 76.5 72.5 2 4.0
1 70.0 90.9 20.9
1 80.4 71.3 2 9.1
1 83.3 85.4 2.1
1 83.0 81.6 2 1.4
1 87.7 89.1 1.4
1 84.2 83.9 2 .3
1 86.4 82.7 2 3.7
1 76.5 75.7 2 .8
1 80.2 82.6 2.4
1 87.8 100.4 12.6
1 83.3 85.2 1.9
1 79.7 83.6 3.9
1 84.5 84.6 .1
1 80.8 96.2 15.4
1 87.4 86.7 2 .7
2 80.7 80.2 2 .5
2 89.4 80.1 2 9.3
2 91.8 86.4 2 5.4
2 74.0 86.3 12.3
2 78.1 76.1 2 2.0
2 88.3 78.1 2 10.2
2 87.3 75.1 2 12.2Group Pretest Posttest Gain
2 75.1 86.7 11.6
2 80.6 73.5 2 7.1
2 78.4 84.6 6.2
2 77.6 77.4 2 0.2
2 88.7 79.5 2 9.2
2 81.3 89.6 8.3
2 78.1 81.4 3.3
2 70.5 81.8 11.3
2 77.3 77.3 0.0
2 85.2 84.2 2 1.0
2 86.0 75.4 2 10.6
2 84.1 79.5 2 4.6
2 79.7 73.0 2 6.7
2 85.5 88.3 2.8
2 84.4 84.7 0.3
2 79.6 81.4 1.8
2 77.5 81.2 3.7
2 72.3 88.2 15.9
2 89.0 78.8 2 10.2
3 83.8 95.2 11.4
3 83.3 94.3 11.0
3 86.0 91.5 5.5
3 82.5 91.9 9.4
3 86.7 100.3 13.6
3 79.6 76.7 2 2.9
3 76.9 76.8 2 0.1
3 94.2 101.6 7.4
3 73.4 94.9 21.5
3 80.5 75.2 2 5.3
3 81.6 77.8 2 3.8
3 82.1 95.5 13.4
3 77.6 90.7 13.1
3 83.5 92.5 9.0
3 89.9 93.8 3.9
3 86.0 91.7 5.7
3 87.3 98.0 10.7a. Run an analysis of variance on group differences in Gain scores.
b. Repeat the analysis, but this time use a repeated measures design where the repeated
measures are Pretest and Posttest.