Chapter 16, Problem 30PS

Using the average baseball salary from 200 through 2017 data for Problem 16.18 on page 645 (stored in BBSalaries).

a. fit a third-order autoregressive model to the average baseball salary and test for the signification of the third-order autoregressive parameter. $(\text{Use}\alpha =\mathrm{0.05.})$

b. if necessary, fit a second-order autoregressive model to the average baseball salary and test for the significance of the second-order autoregressive parameter. $(\text{Use}\alpha =\mathrm{0.05.})$

c. if necessary. Fit a first-order autoregressive model to the average baseball salary and test for the significance of the first order autoregressive parameter. $(\text{Use}\alpha =\mathrm{0.05.})$

d. forecast the average baseball salary for 2018.