Given these sales figures over the first 6 months of the year, your boss needs you to test two different forecasting methods (parts a and b below) to determine which method is best. For your measure of “best”, recommend to your boss that the company should use the method with the lowest mean absolute deviation (MAD). Then use that method to provide your forecast for July in part c.
Jan Feb Mar Apr May Jun
Units sold 25 37 30 38 33 34
a) Calculate the MAD for the 3 period moving average forecasting technique.
b) Calculate the MAD for the 2 period weighted moving average forecasting technique. Use weights of 0.8 and 0.2, with the most recent observation weighted higher.
How many units would you forecast will be sold in July?