Shannon Conducts an Experiment to Test Her Hypothesis That Longer

Multiple Choice

Shannon conducts an experiment to test her hypothesis that longer arguments cause couples to become angrier at each other. She randomly assigns couples to argue for either ten minutes or twenty minutes. After her assistant Ken runs the study, Ken tells Shannon that he allowed the couples who were really fighting hard to keep arguing longer than Shannon had originally stated. Shannon cringes, for she knows that the __________ of her study is very low.

A) random assignment
B) random selection
C) internal validity
D) meaningfulness