An admissions director wants to estimate the mean age of all students enrolled at a college. The estimate must be within 1.6 years of the population mean. Assume the population of ages is normally distributed.

(a) Determine the minimum sample size required to construct a 90% confidence interval for the population mean. Assume the population standard deviation is 1.8 years.

(b) The sample mean is 21 years of age. Using the minimum sample size with a 90% level ofconfidence, does it seem likely that the population mean could be within 10% of the samplemean? within 11% of the samplemean? Explain.