3 In this problem, you are to test the validity of your forecasting model. Here are the forecasts for a model you have been using and the actual demands that occurred: 4 points WEEK 1 2 3 4 5 6 6 FORECAST 790 775 875 875 925 900 ACTUAL 825 925 975 825 825 1,070 eBook a. Use the method stated in the text to compute the MAD and tracking signal for each week. (Negative values should be indicated by a minus sign. Round your "Tracking Signal" to 1 decimal place and all other answers to the nearest whole number.) 100 Hint Week Forecast Actual Deviation Running Sum of Forecast Errors Absolute Deviation Sum of Absolute Deviation Mean Absolute Deviation Tracking Signal Ask 1 825 790 775 2 925 3 875 975 References 4 825 875 925 5 825 6 900 1,070 b. Decide whether the forecasting model you have been using is giving reasonable results. The forecasting model is acceptable The forecasting model is unacceptable