The average amount of sleep students get a night is normally distributed with a mean of 6.5 hours and a standard deviation of 2 hours.

What is the probability that the amount of sleep time by a student selected at random is more than 5 hours? 0.2266
If you select 16 people, what is the probability that their mean amount of sleep time is less than 7 hours? 0.599
If you select 16 people, what is the probability that their mean amount of sleep time is between 5.5 to 7 hours? 0.159