Refer to the data given in Problem 16.17 on page 682 that represent the tons of electronic items recycled from 1999 to 2007 (stored in E-Cycling).
a. Fit a third-order autoregressive model to the tons of electronic items recycled 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 tons of electronic items recycled 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 tons of electronic items recycled and test for the significance of the first-order autoregressive parameter. (Use α = 0.05.)
d. Forecast the tons of electronic items recycled for 2008.