Chapter 17.6, Problem 36E

Refer to exercise 35.

1. a. Deseasonalize the time series using the adjusted seasonal indexes computed in part (c) of exercise 35.
2. b. Using Minitab or Excel, compute the linear trend regression equation for the deseasonalized data.
3. c. Compute the deseasonalized quarterly trend forecast for year 4.
4. d. Use the seasonal indexes to adjust the deseasonalized trend forecasts computed in part (c).

35. Consider the following time series data.

1. a. Construct a time series plot. What type of pattern exists in the data?
2. b. Show the four-quarter and centered moving average values for this time series.
3. c. Compute seasonal indexes and adjusted seasonal indexes for the four quarters.