On weeknights, the average number of hours of sleep per night adults 55–84 years of age get is 7.0. Assume this random variable follows a normal distribution with a standard deviation of 1.1 hours.

a. What is the probability that a randomly selected adult from this age group will get 1. more than 6.0 hours of sleep tonight?

2. less than 5.0 hours of sleep tonight?

3. between 6.3 and 8.0 hours of sleep tonight?

4. between 5.6 and 6.5 hours of sleep tonight?

b. Use Excel or PHStat to confirm the answers in part a.

c. How many hours of sleep will an adult in this age group get if they are in the 35th percentile?

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