Eva and Lucy decide to test the effects of how much sleep a student gets on the academic performance of that student. They select 20 juniors (10 male and 10 female) to study. All students have GPA’s between 3.5 and 4.0, and are all of similar ethnic backgrounds. Eva and Lucy instruct the students to get 9 hours of sleep every night for a week, and give the students a standardized test on Friday. The next week, students are only allowed 8 hours of sleep every night before taking a similar test the following Friday. They continue to vary the amount of sleep down to only 5 hours per night, and record data about how they perform on a standardized test each week.
