Problem#24. Confidence Interval for a Population Mean

A university is conducting research on off-campus housing costs of its students. Data was collected on 1-bedroom rental apartments within a 5-mile radius of the campus. The sample size is 75. The sample mean monthly rent of a 1-bedroom apartment is $1250.

NOTE: Show all your work in Excel.

a) Suppose the population standard deviation is s=$300.  What is the 95% confidence interval for the monthly rent of 1-bedroom apartments? Interpret the confidence interval.

b) Suppose the population standard deviation is unknown and the sample standard deviation is s=$300. What is the 95% confidence interval for the monthly rent of 1-bedroom apartments? Interpret the confidence interval.