Answer:
fatigue.
Step-by-step explanation:
Betsy is conducting a study on school psychologists. She is thinking of having school psychologists complete four experimental conditions each lasting one hour. A colleague suggests to Betsy that she modify the design so that different groups of school psychologists are used and Betsy will not have to worry about fatigue. By using different group of school psychologist, the four experimental conditions will be administered among them and the experiments on the four conditions can run concurrently within an hour thus saving Betsy stress and the fatigue associated with administering the four conditions to only a group of psychologist and spending four hours.