A random sample of 30 college students is selected. Each student is asked how much time he or she spent on homework during the previous week. The following times (in hours) are obtained.19, 17, 18, 25, 24, 18, 17, 20, 20, 21, 22, 25, 18, 20, 24, 16, 17, 15,15, 18, 24, 25, 19, 20, 21, 20, 22, 15, 16, 19Construct a frequency distribution for the data.