Discussion:
In the publication Employment and Earnings, information on the ages of people in the civilian labor force was published. Seventy-five people in the civilian labor force are randomly selected. The mean age is 37.4 years with a standard deviation of 10.3 years.
a. Find the 99% confidence interval for the mean age.
b. What is the error of estimate for the 90% confidence interval?
c. What is the minimum sample size that is needed for the 95% confidence interval, if the maximum error of estimate is 2.1 years?