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: I UARTERLY SALES a) Compute seasonal indexes for the 4 quarters. b) When does the textbook publisher experience the largest change in sales? Does this result appear to be reasonable? Explain. c) 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. (1) Use the selected model to generate a forecast for sales for the rst quarter of Year 4