A researcher uses an anonymous survey to investigate the study habits of American college students. To analyze the impact of group-bases studying on grades, the researcher decided to operationalize group-based studying by asking students how many hours per week they spend studying in a group of 2 or more students. This is the ______ variable. She operationalized grades by asking students what their current cumulative GPA was. This is the ________. Before conducting a hypothesis test, _________ analysis should be conducted in order to look at the distribution of both variables separately. Based on the set of 562 surveys that were completed and returned, the researcher finds that these students have an average cumulative GPA of 2.97. This _______ is an example of a(n) _________.