A textbook publishing company has compiled data on total annual sales of its business textbooks for the preceding eight years: LO4 & LO7 Year: 1 2 3 4 5 6 7 8 Sales (000): 40.2 44.5 48.0 52.3 55.8 57.1 62.4 69.0 Plot the data and fit an appropriate model to it. Forecast the preceding eight years, and determine the forecast errors. Finally, construct a 2s control chart. Using the model, forecast textbook sales for each of the next five years. Suppose actual sales for the next five years turn out as follows: Year: 9 10 11 12 13 Sales (000): 73.7 77.2 82.1 87.8 90.6

1. Calculate the forecast errors for Years 9 to 13.

2. Is the forecasting process in control? Explain.