1. The quarterly sales data (number of copies sold) for a college textbook over the past 3 years are as follows in the Table below:

QUARTERLY SALES
Quarter	Year 1	Year 2	Year 3
1	16	18	18
2	9	9	11
3	26	29	29
4	25	23	26

1. Compute seasonal indexes for the 4 quarters.
2. When does the textbook publisher experience the largest change in sales? Does this result appear to be reasonable? Explain.
3. Using the information on seasonality, compare a 3-quarter moving average to trend projection model and an exponential smoothing with a smoothing constant of 0.1.
4. Use the selected model to generate a forecast for sales for the first quarter of Year 4.