Weinstein, McDermott, and Roediger (2010) published an experimental study examining different techniques that students use to prepare for a test. Students read a passage, knowing that they would have a quiz on the material. After reading the passage, students in one condition were asked to continue studying by simply reading the passage again. In a second condition, students answered a series of prepared questions about the material. Then all students took the quiz. The following table shows quiz scores similar to the results obtained in the study.

Quiz Scores for Two Groups of Students Simply Reread Answer Questions 8, 5, 7, 9, 8 9, 7, 8, 9, 9 9, 9, 8, 6, 9 8, 10, 9, 5, 10 7, 7, 4, 6, 5 7, 9, 8, 7, 8 Sketch a polygon showing the frequency distribution for students who reread the passage. In the same graph, sketch a polygon showing the scores for the students who answered questions. (Use two different colors or use a solid line for one polygon and a dashed line for the other.) Does it look like there is a difference between the two groups?