Modeling an employee's work-hours missed. A large manufacturing firm wants to determine whether a relationship exists between y, the number of work-hours an employee misses per year, and x, the employee's annual wages. A sample of 15 employees produced the data in the accompanying table.
(a) Fit the first-order model, E(y) = β0 + β1x, to the data.
(b) Plot the regression residuals. What do you notice?
(c) After searching through its employees' files, the firm has found that employee #13 had been fired but that his name had not been removed from the active employee payroll. This explains the large accumulation of workhours missed (543) by that employee. In view of this fact, what is your recommendation concerning this outlier?
(d) Measure how influential the observation for employee #13 is on the regression analysis.
(e) Refit the model to the data, excluding the outlier, and compare the results to those in part a.