The monthly sales volume (in thousands of dollars) for a manufacturer of snow skis is seasonal ...

  

Seasonal indexes: Multiplicative model
The monthly sales volume (in thousands of dollars) for a manufacturer of snow skis is seasonal (there tend to be more skis sold during fall and winter months than during warmer months). The following table shows the monthly seasonal indexes for the company's sales:
 

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1.14 1.01 0.96 0.65 0.63 0.46 0.70 0.95 1.24 1.34 1.55 1.37
Using several years of sales data, beginning in August of 1999 (i.e., t=1 corresponds to August of 1999), the manufacturer summarized that the trend line that describes the monthly sales (in thousands of dollars) has the form Tt=323+2t. Assuming that a multiplicative model can be used to describe the sales data, generate a forecast for the total dollar sales the company can expect to receive in January of 2004.