Problem
Ralph Billet is the manager of a real estate agency. He wishes to develop a forecast of the number of houses that will be sold by the agency over the next year. The agency's quarter-by-quarter sales figures over the last three years are shown in the following table:
|
Quarter
|
Year 1
|
Year 2
|
Year 3
|
|
1
|
23
|
19
|
21
|
|
2
|
22
|
21
|
26
|
|
3
|
31
|
27
|
32
|
|
4
|
26
|
24
|
28
|
IMPORTANT: For your convenience, these sales data are also given in the "Final.xlsx" Excel file.
a) Develop a forecasting model that combines possible trend and seasonal effects using the historical data given above. Carefully explain how you developed the model and interpret each slope. Other things being equal, which quarter has the highest sales?
b) What sales would you predict for the second and fourth quarter of the following year (Year 4)?