Problem $3-17($Static$)$

Here are the actual tabulated demands for an item for a nine$-$month period $($January through September$).$ Your supervisor wants to test two forecasting methods to see which method was better over this period.

MONTH ACTUAL

January $110$

February $130$

March $150$

April $170$

May $160$

June $180$

July $140$

August $130$

September $140$

a$.$ Forecast April through September using a three$-$month moving average.

Note: Round your answers to $1$ decimal place.

b$.$ Use simple exponential smoothing with an alpha of $0\mathrm{.}3$ to estimate April through September, using the average of January through March as the initial forecast for April.

Note: Do not round intermediate calculations. Round your answers to $2$ decimal places.

c$-1.$ Calculate MAD for each method.

three$-$month moving average$-$

exponential smoothing$-$

Note: Round your answers to $1$ decimal place.

c$-2.$ Use MAD to decide which method produced the better forecast over the six$-$month period.