Using the data for Problem 16.12 on page 645 concerning the bonuses paid to workers on Wall Street from 2000 to 2016 (stored in Bonuses),

a. Fit a third-order autoregressive model to the bonuses paid and test for the significance of the third-order autoregressive parameter. (Use α = 0.05.)

b. If necessary, fit a second-order autoregressive model to the bonuses paid and test for the significance of the second-order autoregressive parameter. (Use α = 0.05.)

c. If necessary, fit a first-order autoregressive model to the bonuses paid and test for the significance of the first-order autoregressive parameter. (Use α = 0.05.)

d. If appropriate, forecast the bonuses paid in 2017 and 2018.