New car sales for a dealer in Saline County for the past year are shown in the table below, along with monthly indexes (seasonal relatives), which are supplied to the dealer by the regional distributor.
|
Month
|
Units Sold
|
Index
|
|
Month
|
Units Sold
|
Index
|
|
Jan
|
640
|
0.80
|
|
Jul
|
765
|
0.90
|
|
Feb
|
648
|
0.80
|
|
Aug
|
805
|
1.15
|
|
Mar
|
630
|
0.70
|
|
Sep
|
840
|
1.20
|
|
Apr
|
761
|
0.94
|
|
Oct
|
828
|
1.20
|
|
May
|
735
|
0.89
|
|
Nov
|
840
|
1.25
|
|
Jun
|
850
|
1.00
|
|
Dec
|
800
|
1.25
|
Plot the data. Does there seem to be a trend?
Deseasonalize car sale.
Plot deseasonalized data on the same graph as the original data. Comment on the two graphs.
Assuming no proactive approach by management, discuss (do not perform actual calculations) how you would forecast sales for the first three months of next year.
What action might you consider recommending to management based on your analysis?