The file P10_05.xlsx contains salaries for a sample of DataCom employees, along with several variables that might be related to salary.
a. Estimate an appropriate multiple regression equation to predict the annual salary of a given DataCom employee.
b. Given the estimated regression model, predict the annual salary of a male employee who served in a similar department at another company for five years prior to coming to work at DataCom. This man, a graduate of a four-year collegiate business program, has been supervising six subordinates in the sales department since joining the organization seven years ago.
c. Find a 95% prediction interval for the salary earned by the employee in part b.
d. Find a 95% confidence interval for the mean salary earned by all DataCom employees sharing the characteristics provided in part b.
e. How can you explain the difference between the widths of the intervals in parts c and d?