The following tabulations are actual sales of units for six months and a starting forecast in January.
a. Calculate forecasts for the remaining five months using simple exponential smoothing with a = 0.2.
b. Calculate MAD for the forecasts.
Actual
Forecast
January
100
80
February
94
March
106
April
80
May
68
June
94
Solution: Answer- a: Exponential smoothing forecast (a=0.2) Forecast of X month = f(x) ; Actual sales of X month = Y(x) Forecast of February = f(feb) = f(jan)*0.2 + Y(jan)*(1-0.2) =0.2*80 + 0.8*100 = 96 Forecast of March= f(mar) = f(feb)*0.2 +Y(feb)*(1-0.2)=0.2*96 + 0.8*94= 94 Forecast of April= f(apr) = f(mar)*0.2 +Y(mar)*(1-0.2)=0.2*94 + 0.8*106 = 104 Forecast of May= f(may) = f(apr)*0.2 +Y(apr)*(1-0.2)=0.2*104+ 0.8*80= 85 Forecast of June= f(jun) = f(may)*0.2...