1. The quarterly sales data (number of copies sold) for a college textbook over the past 3 years are as follows in Table 2:

Table 2: 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 seasonal index? Does this result appear to be reasonable? Explain.

3. Using the information on seasonality, show a 4-quarter moving average values for this time series and forecast for the 1^st quarter of the 4^th year.