Math Question Help

Question

According to the American Freshman, the number of hours that a college freshman spends studying each week is normally distributed with a mean of 7 hours and a standard deviation of 5.3 hours. Use the 68, 95, 99.7 rule to find the percentage of college freshman who study between 7 and 12.3 hours each week.

Answer 1

12.3 - 7 = 5.3 = one standard deviation

z score = 1

percentage between 7 and 12.3 is 1/2 of 68% = 34%

using the empirical rule of 68-95- 99.7 for 1, 2 and 3 standard deviations from the mean

68% are between 1.7 and 12.3

half of 68% are between 7 and 12.3, the other 34% is between 1.7 and 7