How much do Americans sleep each night? Based on a random sample of 1120 Americans 15 years of age or older, the mean amount of sleep per night is 8.17 according to the American Time Use Survey...

How much do Americans sleep each night?  Based on a random sample of 1120 Americans 15 years of age or older, the mean amount of sleep per night is 8.17 according to the American Time Use Survey conducted by the Bureau of Labor Statistics.  Assuming the population standard deviation for amount of sleep per night is 1.2 hours, construct and interpret a 95% confidence interval for the mean amount of sleep per night of Americans 15 years of age or older.