1. Members of a research team are considering three studies related to sleep and learning. The first study involves comparing the scores on a post-study test of learning from two groups of randomly chosen adults, with one group getting at least 7 hours of sleep per night for a week and the other group getting at most 6 hours of sleep per night for a week. A second study involves asking a random sample of students at a large university to report the average number of hours of sleep they get each night and their college grade point average. A third study involves asking a random sample of high school students in a large school district whether they feel they get enough sleep to stay alert throughout the school day.