Answer:
3
Step-by-step explanation:
Data provided in the question:
Sales for the last four months :
8, 10, 15, and 9 units
Last four forecast of sales:
9, 11, 8 and 12 units
Now,
The mean absolute deviation (MAD) value of these forecast will be calculated as:
MAD = [ ∑|Sales - Forecast sales| ] ÷ [ Total number of forecast ]
or
MAD = [ |8 - 9| + |10 - 11| + |15 - 8| + |9 - 12| ] ÷ 4
or
MAD = [ 1 + 1 + 7 + 3 ] ÷ 4
or
MAD = 12 ÷ 4
or
MAD = 3