A survey of 656 boys and girls, ages 13 to 18 years old, asked about adequate sleep and other health-related behaviors. The recommended amount of sleep is six to eight hours per night.! In the survey, 54% of the respondents reported that they got less than this amount of sleep on school nights. An exercise scale was developed and used to classity the students as above or below the median in this domain. Here is the 2 x 2 table of counts with students classified as getting or not getting adequate sleep and by the exercise variable: Exercise Enough Sleep High Low Yes 151 115 No 148 242