Question

Suppose that hours of sleep per night for single adults between 30 and 40 years of age are normally distributed with a mean of 6.7 hours and a standard deviation of 1.1 hours. What proportion of adults sleep longer than 4.5 hours per night? (Report to 3 decimal places.)

Answer 1

http://davidmlane.com/hyperstat/z_table.html

Answer 2

7.54

Answer 3

0.977