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?