In this exercise we consider annual U.S. lumber production over 30 years. The data were obtained from the U.S. Department of Commerce Survey of Current Business and are presented in Table 15.5. (The lumber production values are given in millions of board feet.) Plot the lumber production values versus time and discuss why the plot indicates that the model y_t = β₀ + ε_t might appropriately describe these values.

Table 15.5

Annual Total U.S............Lumber Production

35,404........................................35,733
37,462........................................35,791
32,901........................................34,592
33,178........................................38,902
34,449........................................37,858
38,044........................................32,926
36,762........................................35,697
36,742........................................34,548
33,385........................................32,087
34,171........................................37,515
36,124........................................38,629
38,658........................................32,019
32,901........................................35,710
36,356........................................36,693
37,166........................................37,153