Two independent methods of forecasting based on judgment and experience have been prepared each month for the past 10 months. The forecasts and actual sales are as follows:
WORKING AREA FOR
MODEL 1 MODEL 2 MODEL 3
Month Sales F1 F2 F3
1 770 771 769 774
2 789 785 787
3 794 790 792
4 780 784 798
5 768 770 774
6 772 768 770
7 760 761 759
8 775 771 775
9 786 784 788
10 790 788 788
Performance Measurements
CFE
MAD
MSE
What are the 2s control limits for the third model? Plot the error terms. What is your conclusion about the forecasting model?