8. In an effort to reduce this prejudice before it becomes too ingrained, a researcher designs a study to have fourth-year medical students see videos of 10 patients (who are really actors) a month apart. In one sequence of the 10 videos, an actor is made up to look about 70 and talks about being retired, and in the other sequence of the 10 videos, the same actor is depicted as his own age (30). The actor presents similar complaints in each video. Students are randomly assigned to the order of viewing these two sequence of videos a month apart. After viewing each of the videos, the students list the questions they would ask the patient, their diagnosis of the complaint(s), and their rating of concern for the health of the "patient" on a 15-point scale, with higher scores representing more concerns. The researcher is interested in comparing the level of concern given to a "young" vs. "old" patient given the same complaints. What potential problem(s) do you identify in the study design