Question

# a. The number of hours of sleep per night that adults in the United States is...

a. The number of hours of sleep per night that adults in the United States is normally distributed with a mean of 6.8 hours and a standard deviation of 1.4 hours. If the recommended amount of sleep is 7 hours, what proportion of US adults are getting less than that amount of sleep? Round to the nearest ten-thousandth.

b. The number of hours of sleep per night that adults in the United States is normally distributed with a mean of 6.8 hours and a standard deviation of 1.4 hours. Out of 100 US adults, how many would you expect to get between 8 and 9 hours of sleep? Round to the nearest whole number. We would expect ___ adults to get between 8 and 9 hours of sleep.

c.The number of hours of sleep per night that adults in the United States is normally distributed with a mean of 6.8 hours and a standard deviation of 1.4 hours. What number of hours of sleep is at the 30th percentile? Round to the nearest ten-thousandth (4 decimal places).___ hours is at the 30th percentile.

d. The number of hours of sleep per night that adults in the United States is normally distributed with a mean of 6.8 hours and a standard deviation of 1.4 hours. Would it be considered unusual for a person to get at least 9 hours of sleep? Why or why not?

It ["would not", "would"] be unusual since the probability is ["greater than", "less than", "equal to"] 0.05.

e. The number of hours of sleep per night that adults in the United States is normally distributed with a mean of 6.8 hours and a standard deviation of 1.4 hours. A simple random sample of 100 people is selected. What is the probability that the mean of the sample is greater than 7 hours? Round to the nearest ten-thousandth