Question: Given the weekly demand data, what are the exponential smoothing forecasts for periods 2-05 using a=0.10?
Week | Demand | 0.1 |
1 | 980 |
|
2 | 825 |
|
3 | 760 |
|
4 | 650 |
|
5 |
|
|
Note: Calculation along with the formula is required for each period's forecast. Students who give answers without calculation will be given low marks/no marks.
Ans
Formula
Ft= Ft-1 + a (At-1 – Ft-1)
Ft = Forecast value for the coming time period
F t−1 = Forecast value in 1 past time period
At−1 = Actual occurrence in the 1 past time period
α = Alpha smoothing constant
Week | Demand | 0.1 | Calculations |
1 | 980 | 980 | =980+.10(0) = 980 |
2 | 825 | 980 | =980+.10(980-980) =980+.10 (0) =980 |
3 | 760 | 964.50 | =980+.10(825-980) =980+.10(-155) =980-15.5 =964.50 |
4 | 650 | 944.05 | =964.50+.10 (760-964.50) =964.50 +.10 (-204.5) =964.50 – 20.45 =944.05 |
5 |
| 914.645 | = 944.05+.10(650-944.05) =944.05 +.10(-294.05) =944.05 – 29.405 =914.645 |
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