The monthly sales for Telco Batteries, Inc., were as follows:
Month Sales
January............. 20
February ............. 21
March. ............. 15
April.............. 14
May............... 13
June............... 16
July ............... 17
August.............. 18
September............ 20
October............. 20
November............ 21
December............ 23
(a) Plot the monthly sales data.
(b) Forecast January sales using each of the following:
(i) Naïve method.
(ii) A 3-month moving average.
(iii) A 6-month weighted average using .1, .1, .1, .2, .2, and .3, with the heaviest weights applied to the most recent months.
(iv) Exponential smoothing using an α = .3 and a September forecast of 18.
(v) A trend projection.
(c) With the data given, which method would allow you to forecast next March’s sales?