Costs are rising for all kinds of medical care. The mean monthly rent at assisted­living facilities was reported to have increased 17% over the last five years to $3486. Assume this cost estimate is based on a sample of 120 facilities and, from past studies, it can be assumed that the population standard deviation is s 5 $650. a. Develop a 90% confidence interval estimate of the population mean monthly rent. b. Develop a 95% confidence interval estimate of the population mean monthly rent. c. Develop a 99% confidence interval estimate of the population mean monthly rent. d. What happens to the width of the confidence interval as the confidence level is increased? Does this seem reasonable? Explain.