P-5) (30 Pts.) One of the spare parts for B category of automobiles has the following demand history over a 24 periods (months): 15 MONTH DEMAND MONTH DEMAND 1 160 13 148 2 174 14 168 3 178 179 4 167 16 165 5 153 17 150 6 178 18 172 7 181 19 179 8 176 20 161 9 143 21 155 10 173 22 165 11 191 23 181 177 24 164 12 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.) c. Using a = 0.2 and = 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 (7th, 8th and 9th periods)? (10 Pts.) P-5) (30 Pts.) One of the spare parts for B category of automobiles has the following demand history over a 24 periods (months): 15 MONTH DEMAND MONTH DEMAND 1 160 13 148 2 174 14 168 3 178 179 4 167 16 165 5 153 17 150 6 178 18 172 7 181 19 179 8 176 20 161 9 143 21 155 10 173 22 165 11 191 23 181 177 24 164 12 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.) c. Using a = 0.2 and = 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 (7th, 8th and 9th periods)? (10 Pts.)