Respond to the following :
1. 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 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?
2. Lenovo uses the ZX-81 chip in some of its laptop computers. The prices for the chip during the past 12 months were as follows:
|
MONTH
|
PRICE PERCHIP
|
MONTH
|
PRICE PERCHIP
|
|
January
|
$1.80
|
July
|
1.80
|
|
February
|
1.67
|
August
|
1.83
|
|
March
|
1.70
|
September
|
1.70
|
|
April
|
1.85
|
October
|
1.65
|
|
May
|
1.90
|
November
|
1.70
|
|
June
|
1.87
|
December
|
1.75
|
a)Use a 2-month moving average on all the data and plot the averages and the prices.
b)Use a 3-month moving average and add the 3-month plot to the graph created in part (a).
c)Which is better (using the mean absolute deviation): the 2-month average or the 3-month average?
d)Compute the forecasts for each month using exponential smoothing, with an initial forecast for January of $1.80. Use α = .1, then α = .3, and finally α = .5. Using MAD, which a is the best?