Refer to Exercise 12.13. Fit a cubic model to the data, and then answer the following questions.
a. Can the hypothesis of no overall predictive value be rejected at the a 5 0.01 level? Justify your answer.
b. Test the research hypothesis H0: b3 = 0 at the α = 0.05 level. Report the p- value of the test.
c. Based on the results of the test in part (b), display the estimated regression model.
d. Plot the data along with the best- fitting estimated regression line.