Question: Suppose that a researcher hypothesized that it was harder to get into psychology graduate programs than it was to get into history graduate programs. To test this hypothesis, she randomly selected 25 universities (IU, Harvard, Michigan, etc.) that had graduate programs in both psychology and history. She then recorded the average GPA for the applicants to each school's psychology program and to each school's history program. A small sample of the data is provided below. What is the study design for this research?