Sales of industrial vacuum cleaners at R. Lowenthal Supply Co. over the past 13 months are as follows:

SALES ($1,000s)	MONTH
11	Jan
14	Feb
16	Mar
10	April
15	May
17	Jun
11	Jul
14	Aug
17	Sep
12	Oct
14	Nov
16	Dec
11	Jan

(a) Using a moving average with three periods, determine the demand for vacuum cleaners for next February. (b) Using a weighted moving average with three periods, determine the demand for vacuum cleaners for February. Use 3, 2, and 1 for the weights of the most recent, second most recent, and third most recent periods, respectively. For example, if you were forecasting the demand for February, November would have a weight of 1, December would have a weight of 2, and January would have a weight of 3. (c) Evaluate the accuracy of each of these methods. (d) What other factors might R. Lowenthal consider in forecasting sales?