Assume that you are part of a wellness group who want to mandate an hour of physical activity for staff in a hospital each time they go on duty. You want to develop a study that offers evidence that they benefit from such activity. Which do you want to avoid asserting from any evidence you develop?

a. that the results are probably related to the staff’s physical activity and family supports outside of the school as well as in-school activity
b. that the results can be generalized to all hospital staff
c. that the results should be looked at over time rather than as a single measure
d. that the results might be different if you changed the time of the physical activity