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 740 820 920 920 970 945 ACTUAL 870 970 1,020 870 870 1,020 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.) Woek Forecast Actual Deviation RSFE Absolute Deviation Sum of Absolute Deviation MAD TS 740 1 2 820 3 4 920 920 970 945 870 970 1,020 870 870 1,020 5 6