Madelyn Davis is a research analyst for a large investment firm. She has been assigned the task of forecasting sales for W al-Mart Stores, Inc., for fiscal year 2011. She collects quarterly sales for Wal-Mart Stores, Inc. (in millions $) for the 10-year period 2001 through 2010, a portion of which is shown in the accompanying table. The full data set is on the text website, labeled Wal-Mart Sales.
Wal-Mart Quarterly Sales (in millions $)
|
|
Quarters Ended
|
|
Years
|
April 30
|
July 31
|
October 31
|
January 31
|
|
2001
|
42,985
|
46,112
|
45,676
|
56,556
|
|
2002
|
48,052
|
52,799
|
52,738
|
64,210
|
|
....
|
....
|
....
|
....
|
....
|
|
2010
|
93,471
|
100,082
|
98,667
|
112,826
|
In a report, use the sample information to:
1. Use a scatterplot to determine which model best depicts trend for Wal-Mart's sales.
2. Determine whether or not a seasonal component exists in the series, using the seasonal dummy variable approach.
3. Given the conclusions on trend and the seasonal component, provide forecast values for the four quarters of 2011 as well as total projected sales for fiscal year 2011.