Sales of industrial vacuum cleaners at Overholt Supply Co. over the past 13 months were as follows:

Month	Sales (thousands)	Month	Sales (thousands)
January	9	August	12
February	12	September	15
March	14	October	10
April	8	November	12
May	13	December	14
June	15	January	9
July	9

(a) Using a moving average with three periods, determine the demand for vacuum cleaners for next February.

(b) Using a three-period weighted moving average with weights 3, 2, and 1 (3 = most recent), determine the demand for vacuum cleaners for February.

(c) Evaluate and comment on the accuracy of each of these models.

Please show work in Excel