Q4 (W4, Forecasting and Errors) Assuming the following data are the forecasts over the last 20 seasons. Please answer the following questions. [Note you need to work on Excel and expand this table.) a) Please calculate the forecast values for Moving average (n=4), weighted moving average (w1=0.1, W2=0.1, w3=0.3, and w4=0.5, where w1 is for 4-week old period, and w4 is for the most recent period.) and Exponential smoothing (alpha=0.2) from Season 1 to Season 20. b) Please use forecasting error measures (Forecast error, MAD, MSE & MAPE) to evaluate the three forecasting methods. Which forecasting method is the best? c) Please calculate the tracking signals for three forecasting methods from Season 5 to Season 20. Based on tracking signals, which forecasting method is the best? Season Exp. Smooth Exp. Smooth Spring Summer Fall Winter Spring Summer Fall Winter Spring Summer Real Period MA WMA Demand 1 1035 2 1095 3 1196 4 1094 5 1139 6 1220 7 1194 8 1167 9 1269 10 1210 Real Season Period MA WMA Demand Fall 11 1318 Winter 12 1195 Spring 13 1246 Summer 14 1352 Fall 15 1377 Winter 16 1300 Spring 17 1341 Summer 18 1480 Fall 19 1384 Winter 20 1402