In this problem 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 16.5
a. Plot the lumber production values versus time and discuss why the plot indicates that the model
yt = β0 + εt,
might appropriately describe these values.
b. The mean and the standard deviation of the lumber production values can be calculated to be  = 35,651.9 and s = 2,037.3599. Find a point forecast of and a 95 percent prediction interval for any future lumber production value.