Athletes who had suffered brokenlegs

were randomly assigned to one of two exercise programs. The first group returned to sports activities in a mean of 61.2

days (with a standard deviation of

24.7 days). The other group returned to sports in a mean of 51.7

days (with a standard deviation of 14.2

days).

2) There was no control group of athletes who did not participate in a special exercise program. Explain the advantage of including such a group in this experiment.

a) A control group could have revealed why one program was more successful at healing the injury than the other A control group could have revealed whether either exercise program was better or worse than just letting the injury heal without exercise. A control group could have revealed whether either exercise program was better or worse than just letting the injury heal without exercise.

b) A control group could have revealed whether participating in both exercise programs was better or worse than participating in only one.

c) A control group could have revealed why one program was more successful at healing the injury than the other.