The monthly sales for Yazici 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) Naive 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 a = .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? (MyLab Operations Management also includes a shorter (brief) version of this problem.)