Fix It Dave Is a Second-Year Graduate Student Working on His Thesis

Fix It
Dave is a second-year graduate student working on his thesis. He predicts that olfaction is an important factor affecting food consumption. To that end, he obtains a group of rats and randomly assigns them to two treatment conditions. The rats in group one receive standard rat chow. The rats in group two receive a rat chow that is manufactured to have no scent. Dave convinces his advisor that he needs research assistants to help him with his study. Dave's advisor calls the director of the university's work-study program who sends two students to work with Dave. One work-study student, Robin, assigned to help Dave also works part-time in the cafeteria. From 9 a.m. to noon she works at Fiesta Cantina, and from 12:30 to 3:00 she works with Dave. The other work-study student, Patrick, has no other responsibilities than to work with Dave. Dave randomly assigned each student to work with one group of rats. Patrick was assigned the control group and Robin was assigned the experimental group. Their job is to give each rat 25 grams of rat chow. After 1 hour they measure how much of the food has been consumed by each rat. The remaining food is removed and the rats are not fed again until the following day. Dave compares the mean amount of food eaten by rats from each group. He finds that rats in the standard chow group consume just as much food as those in the unscented food. Although contrary to his prediction, Dave concludes that food scent is not associated with food consumption.
What type of research design did Dave create? Why do you think Dave did not find a difference between the groups? Fix it!