Problem:

1. The monthly sales for Telco Batteries, Inc., were as follows: Month Sales

Jan 20
Feb 21
Mar 15
Apr 14
May 13
Jun 16
Jul 17
Aug 18
Sep 20
Oct 20
Nov 21
Dec 23

Required:

Question 1) Plot the monthly sales data on a sheet of graph paper.

Question 2) Forecast January sales for the new year using each of the following:

1) Basic naïve method.
2) A 3-month moving average.
3) A 6-month weighted moving average using 0.1, 0.1, 0.1, 0.2, 0.2, 0.3, with the heaviest weights applied to the most recent months.
4) Exponential smoothing using a smoothing constant of 0.3 and a September forecast of 18 (note that you must compute forecasts for Oct, Nov, and Dec before computing the one for January).
5) A trend projection using the least squares method

Question 3) With the data given,which method would allow you to forecast next March's sales?

Solve the given numerical problem and illustrate step by step calculation.