The typical amount of sleep per night for college students has a bell-shaped distribution with a mean of 7 hours and a standard deviation equal to 1.7 hours. Use the Empirical Rule to complete each sentence:
a. About 68% of college students typically sleep between and hours per night.
b. About 95% of college students typically sleep between and hours per night.
c. About 99.7% of college students typically sleep between and hours per night.