In: Statistics and Probability
Question2:
A manager use his company profit time series for one goods to calculate forecast for upcoming years. He use
F1 = Moving Average Method for 3 years
F2 = Weight Moving Average for 3 years
F3 = Exponential Smoothing Method with α = 0.2
F4 = Exponential Smoothing Method with α = 0.7
His calculation represent in the following table. Gide the manager to chose the better method by calculate MAD and MES for each method
| 
 t  | 
 y  | 
 F1=MA(3)  | 
 F2=WMA(3)  | 
 F3=exp(0.2)  | 
 F4=exp(0.7)  | 
| 
 1  | 
 58  | 
 -  | 
 -  | 
 -  | 
 -  | 
| 
 2  | 
 46  | 
 -  | 
 -  | 
 58.0  | 
 58.0  | 
| 
 3  | 
 55  | 
 -  | 
 -  | 
 55.6  | 
 49.6  | 
| 
 4  | 
 39  | 
 53.0  | 
 53.5  | 
 55.5  | 
 53.4  | 
| 
 5  | 
 42  | 
 46.7  | 
 42.9  | 
 52.2  | 
 43.3  | 
| 
 6  | 
 63  | 
 45.3  | 
 42.7  | 
 50.1  | 
 42.4  | 
| 
 7  | 
 54  | 
 48.0  | 
 56.4  | 
 52.7  | 
 56.8  | 
| 
 8  | 
 55  | 
 53.0  | 
 54.6  | 
 53.0  | 
 54.8  | 
| 
 9  | 
 61  | 
 57.3  | 
 55.6  | 
 53.4  | 
 55.0  | 
| 
 10  | 
 52  | 
 56.7  | 
 59.1  | 
 54.9  | 
 59.2  | 
| 
 11  | 
 -  | 
 56.0  | 
 54.1  | 
 54.3  | 
 54.2  | 
F1:
| period | demand | forcast | forecast error=demand value-forecast value | absolute forecast error | squared forcast error | 
| t | Dt | Ft | et=Dt-Ft | | et | | (et)² | 
| 1 | 58 | ||||
| 2 | 46 | ||||
| 3 | 55 | ||||
| 4 | 39 | 53.000 | -14.00 | 14.00 | 196.00 | 
| 5 | 42 | 46.700 | -4.70 | 4.70 | 22.09 | 
| 6 | 63 | 45.300 | 17.70 | 17.70 | 313.29 | 
| 7 | 54 | 48.000 | 6.00 | 6.00 | 36.00 | 
| 8 | 55 | 53.000 | 2.00 | 2.00 | 4.00 | 
| 9 | 61 | 57.300 | 3.70 | 3.70 | 13.69 | 
| 10 | 52 | 56.700 | -4.70 | 4.70 | 22.09 | 
MAD/MAE=   Σ |et|/n =    7.54
      
MSE=   Σ(et)²/n =    86.74
---------------------------------------------------------------------------
F2:
| period | demand | forcast | forecast error=demand value-forecast value | absolute forecast error | squared forcast error | 
| t | Dt | Ft | et=Dt-Ft | | et | | (et)² | 
| 1 | 58 | ||||
| 2 | 46 | ||||
| 3 | 55 | ||||
| 4 | 39 | 53.500 | -14.50 | 14.50 | 210.25 | 
| 5 | 42 | 42.900 | -0.90 | 0.90 | 0.81 | 
| 6 | 63 | 42.700 | 20.30 | 20.30 | 412.09 | 
| 7 | 54 | 56.400 | -2.40 | 2.40 | 5.76 | 
| 8 | 55 | 54.600 | 0.40 | 0.40 | 0.16 | 
| 9 | 61 | 55.600 | 5.40 | 5.40 | 29.16 | 
| 10 | 52 | 59.100 | -7.10 | 7.10 | 50.41 | 
MAD/MAE=   Σ |et|/n =    7.29
      
MSE=   Σ(et)²/n =    101.23
----------------------------------------------
F3
| period | demand | forcast | forecast error=demand value-forecast value | absolute forecast error | squared forcast error | 
| t | Dt | Ft | et=Dt-Ft | | et | | (et)² | 
| 1 | 58 | ||||
| 2 | 46 | 58.000 | -12.00 | 12.00 | 144.00 | 
| 3 | 55 | 55.600 | -0.60 | 0.60 | 0.36 | 
| 4 | 39 | 55.500 | -16.50 | 16.50 | 272.25 | 
| 5 | 42 | 52.200 | -10.20 | 10.20 | 104.04 | 
| 6 | 63 | 50.100 | 12.90 | 12.90 | 166.41 | 
| 7 | 54 | 52.700 | 1.30 | 1.30 | 1.69 | 
| 8 | 55 | 53.000 | 2.00 | 2.00 | 4.00 | 
| 9 | 61 | 53.400 | 7.60 | 7.60 | 57.76 | 
| 10 | 52 | 54.900 | -2.90 | 2.90 | 8.41 | 
MAD/MAE=   Σ |et|/n =    7.33
      
MSE=   Σ(et)²/n =    84.32
-----------------------------
F4
| period | demand | forcast | forecast error=demand value-forecast value | absolute forecast error | squared forcast error | 
| t | Dt | Ft | et=Dt-Ft | | et | | (et)² | 
| 1 | 58 | ||||
| 2 | 46 | 58.000 | -12.00 | 12.00 | 144.00 | 
| 3 | 55 | 49.600 | 5.40 | 5.40 | 29.16 | 
| 4 | 39 | 53.400 | -14.40 | 14.40 | 207.36 | 
| 5 | 42 | 43.300 | -1.30 | 1.30 | 1.69 | 
| 6 | 63 | 42.400 | 20.60 | 20.60 | 424.36 | 
| 7 | 54 | 56.800 | -2.80 | 2.80 | 7.84 | 
| 8 | 55 | 54.800 | 0.20 | 0.20 | 0.04 | 
| 9 | 61 | 55.000 | 6.00 | 6.00 | 36.00 | 
| 10 | 52 | 59.200 | -7.20 | 7.20 | 51.84 | 
MAD/MAE=   Σ |et|/n =    7.77
      
MSE=   Σ(et)²/n =    100.25
--------------------------------------------------------
Hence we can say that F3 is the best method
Please revert back in case of any doubt.
Please upvote. Thanks in advance.