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

Month	Actual Demand
Jan	120
Feb	140
March	160
April	180
May	170
June	190
July	150
August	160
September	170

a. Forecast April through September using a three-month moving average and calculate MAD for the forecasts.

b.Forecast May through September using a four-month moving average and calculate MAD for the forecasts.

(Please provide detailed steps of your solution for part a and b.)