The quarterly sales data (number of copies) for a college textbook over the past three years follow. quarter 1 2 3 4 year 1 1690 940 2625 2500 year 2 1800 900 2900 2360 year 3 1850 1100 2930 2615 a. Construct a time series plot. What time of pattern exists in the data? b. Show the four-quartered and centered moving average values for this time series. c. Compute the seasonal and adjusted seasonal indexes for the four quarters, d. When does the publisher have the largest seasonal indexes? Does this result appear reasonable? Explain. e. Deseasonalize the time series. f. Compute the linear trend equation for the deseasonalized data and forecast sales using the linear trend equation. g. Adjust the linear trend forecasts using the adjusted seasonal indexes computed in part (c).