Harlen Industries has a simple forecasting model: Take the actual demand for the same month last year and divide that by the number of fractional weeks in that month. This gives the average weekly demand for that month. This weekly average is used as the weekly forecast for the same month this year. This technique was used to forecast eight weeks for this year, which are shown in the following tables along with the actual demand that occurred.

The following eight weeks show the forecast $($based on last year$)$ and the demand that actually occurred:

WEEK FORECAST DEMAND ACTUAL DEMAND

$1140137$

$2140133$

$3130144$

$4137154$

$5132174$

$6142164$

$7165178$

$8142198$

Compute the MAD of forecast errors.