The Quarterly Sales of a Company (In Millions of Dollars)

Essay

The quarterly sales of a company (in millions of dollars) over the past three years are given in the following table. ​
a.
Compute the four seasonal indexes.
b.
The trend for these data is Trend = 20.82 + .336t (t represents time, where t = 1 for Quarter 1 of 2013 and t = 12 for Quarter 4 of 2015). Forecast sales for the first quarter of 2016 using the trend only.
c.
Forecast sales for the first quarter of 2016 using the trend and seasonal indexes and write your answer below.