Problem 3-20 (Algo) 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: WEEK 1 2 3 4 5 6 FORECAST 730 810 910 910 960 935 ACTUAL 860 960 1,010 860 860 1,010 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 2 decimal place and all other answers to the nearest whole number.) Week Forecast Actual Deviation RSFE Absolute Deviation Sum of Absolute Deviation MAD TS 1 730 860 2 810 960 1,010 3 910 4 910 860 5 960 860 6 6 935 1,010 b. Decide whether the forecasting model you have been using is giving reasonable results. The forecasting model is acceptable The forecasting model is unacceptable