P-5) (30 Pts.) One of the spare parts for B category of automobiles has the following demand history over a 24 periods (months): MONTH 1 2 3 4 5 6 7 8 9 10 11 12 DEMAND MONTH 160 13 174 14 178 15 167 16 153 17 178 18 181 19 176 20 143 21 173 22 191 23 177 24 DEMAND 148 168 179 165 150 172 179 161 155 165 181 164 a. Make a "time series plot of the data and verify that it is seasonal. Why do you think that the seasonality is presentot present in these data? (5 pts) b. Using the data from Years 1 and 8. determine initial values of the intercept, slope, and seasonal factors for Winters's method. (5 Pts.) e. Using a = 0.2 and 8 = 0.3. and y = 0.4 update the estimates of the series, the slope, and the seasonal factors. (10 Pts.) d What are the forecasts made at the end of the sixth period for the next three periods (74.8" and 9" periods)? (10 PES.) P-5) (30 Pts.) One of the spare parts for B category of automobiles has the following demand history over a 24 periods (months): MONTH 1 2 3 4 5 6 7 8 9 10 11 12 DEMAND MONTH 160 13 174 14 178 15 167 16 153 17 178 18 181 19 176 20 143 21 173 22 191 23 177 24 DEMAND 148 168 179 165 150 172 179 161 155 165 181 164 a. Make a "time series plot of the data and verify that it is seasonal. Why do you think that the seasonality is presentot present in these data? (5 pts) b. Using the data from Years 1 and 8. determine initial values of the intercept, slope, and seasonal factors for Winters's method. (5 Pts.) e. Using a = 0.2 and 8 = 0.3. and y = 0.4 update the estimates of the series, the slope, and the seasonal factors. (10 Pts.) d What are the forecasts made at the end of the sixth period for the next three periods (74.8" and 9" periods)? (10 PES.)