Each student in the class keeps a log of the hours he/she spends studying in a group. Students report the total number of study hours after the course is completed. Students are randomly assigned to two groups. One is assigned to only study on an individual basis, while the other is assigned to participate in group study sessions. Students are randomly assigned to four groups. Each group votes on how much studying they will do, and then studies that amount each week. Students are randomly assigned to four study groups. The instructor then randomly assigns a different number of study hours to each group. The instructor puts all of the freshmen in the class into one group, all of the sophomores into another, all of the juniors into another, and finally all of the seniors into another. The instructor then randomly picks a certain number of hours for each group to study per week. Four groups are set up. Students in the first group are assigned to not study at all. Students in the second group are assigned to study on an individual basis. Students in the 3rd group are assigned to study 2 hours per week. Students in the 4th group are assigned to study 4 hours per week. Students then choose which group they want to be in.