Sale of the industrial vacuum cleaners at R. Lowenthal Supply Co. over the past 13 months are as follows:
Sales (1,000) Month Sales (1,000s) Month
11 January 14 August
14 February 17 September
16 March 12 October
10 April 14 November
15 May 16 December
17 June 11 January
11 July
(a) Using moving average with three periods, find out the demand for vacuum cleaners for next February.
(b) Using weighted moving average with three periods, find out the demand for vacuum cleaners for February. Use 3, 2, and 1 for the weights of most recent, second most recent, and third most recent periods, respectively. For example, if you were forecasting the demand for February, November would have weight of 1, December would have a weight of 2, and January would have a weight of 3.
(c) Determine the accuracy of each of these techniques.
(d) What other factors might R. Lowenthal consider in forecasting sales?