Since May of 2005, the purchase manager at department store has been using the 4-period moving average to forecast sales in next months. Sales data for months of January through July are given in the table below.
|
Month
|
Sales
|
|
Jan
|
65
|
|
Feb
|
65
|
|
Mar
|
41
|
|
Apr
|
50
|
|
May
|
63
|
|
June
|
38
|
|
Jul
|
72
|
Evaluate the mean absolute deviation (or MAD) for four-period moving average forecasts. The forecast values are computed with accuracy of two decimal digits. Identify the MAD as an entire number by rounding.