Does the type of program people watch influence how much they eat? A total of 94 college students were randomly assigned to one of three treatments: watching 20 minutes of a Hollywood action movie (The Island), watching the same 20-minute excerpt of the movie with no sound, and watching 20 minutes of an interview program (Charlie Rose). While watching, participants were given snacks (M&M’S®, cookies, carrots, and grapes) and allowed to eat as much as they wanted. Subjects who watched the highly stimulating excerpt from The Island ate 65% more calories than subjects who watched Charlie Rose. Participants who watched the silent version of The Island ate 46% more calories than those who watched Charlie Rose. Identify the explanatory and response variables in this study. Then determine if it is an experiment or an observational study. Explain your reasoning.