#3.13. Refer to Copier maintenance Problem 1.20. a. What are the alternative conclusions when testing for lack of fit of a linear regression function? b. Perform the test indicated in part (a). Control the risk of Type I error at .05. State the decision rule and conclusion. c. Does the test in part (b) detect other departures from regression model (2.1), such as lack of constant variance or lack of normality in the error terms? Could the results of the test of lack of fit be affected by such departures? Discuss