A researcher wishes to estimate the number of days it takes an automobile dealer to sell a Chevrolet Aveo. A random sample of 50 cars had a sample mean time on the dealer's lot of 54 days. Assume the population standard deviation to be 6.0 days.

(a) What is value of the population mean?

(b) Develop a 95 percent confidence interval for the population mean.

(c) Interpret the results in part b.