A textbook publishing company has compiled data on total annual sales of its business texts for the preceding nine years: 2 7 8 9 Year Sales (000): 38.30 44.10 48.90 4 5 6 50.90 54.70 57.40 64.00 69.50 74.60 Click here for the Excel Data File a. Using an appropriate model, forecast textbook sales for each of the next five years. (Round your intermediate calculations to 2 decimal places and final answers to 2 decimal places.) 13 12 11 14 Year 10 90.24 81.64 77.33 Forecast 85.94 94.54 b. Compute +/- 2s control limits for the control chart for forecast errors using just data from the original nine periods. (Round intermediate calculations to 4 decimal places and final answer to 2 decimal places.) Control limits are 0 c. Suppose actual sales for the next five years turn out as follows: 11 Year 10 77.00 82.90 13 12 92.10 87.20 14 98.10 Sales (000): Is the forecast performing adequately? O No Yes