Executives at a large corporation hired a psychologist to evaluate two physical fitness programs that differed specifically in the degree to which diet and nutritional suggestions were part of the
program. Both plans required regular exercise but Plan N included diet/nutritional requirements for
all participants while Plan E only emphasized a regular exercise program for all participants, but did
not require participants to change their eating habits. The nature and amount of exercise required
in the two programs were essentially the same. Two hundred employees were placed in equal
numbers (100) to either Program Nor Program E. Each program lasted 6 months, during which time
employee absenteeism in each group was monitored. At the end of the program, participants were
given a questionnaire designed to assess attitudes toward the company and the fitness program.
Because of transfers within the company, firing and quitting of employees, and other reasons not
able to be documented, only 75 out of 100 employees in Group E finished the program, and only 50
of the original 100 participants from Program N completed the 6-month program. The psychologist
judged that these sample sizes were still sufficiently large enough to assess adequately the effect of