The Health Care Cost Institute tracks health care expenditures for beneficiaries under the age of 65 who are covered by employer-sponsored private health insurance (Health Care Cost Institute website, November 4, 2012). The data contained in the file named DrugCost are consistent with the institute’s findings concerning annual prescription costs per employee. Analyze the data using Excel or Minitab and answer the following questions.

a. Develop a 90% confidence interval for the annual cost of prescription drugs.

b. Develop a 90% confidence interval for the amount of out-of-pocket expense per employee.

c. What is your point estimate of the proportion of employees who incurred no prescription drug costs?

d. Which, if either, of the confidence intervals in parts (a) and (b) has a larger margin of error? Why?