Sleep The amounts of times that adults sleep are normally distributed with a mean of 6.8 hours and a standard deviation of 1.4 hours (based on data from multiple sources, including a Gallup poll and the American Journal of Epidemiology). A common recommendation is that we get between 7 and 9 hours of sleep each night.

a. For someone randomly selected, find the probability that they get between 7 and 9 hours of sleep in a night.

b. If we randomly collect a sample of 5 adults, what is the probability that the sample mean is between 7 hours and 9 hours?