The quarterly sales data (number of copies sold) for a college textbook over the past three years
Question:
a. Construct a time series plot. What type of pattern exists in the data?
b. Use an Excel or LINGO model with dummy variables as follows to develop an equation to account for seasonal effects in the data. Qtr1 = 1 if Quarter 1, 0 otherwise; Qtr2 = 1 if Quarter 2, 0 otherwise; Qtr3 = 1 if Quarter 3, 0 otherwise.
c. Compute the quarterly forecasts for next year.
d. Let t = 1 to refer to the observation in quarter 1 of year 1; t = 2 to refer to the observation in quarter 2 of year 1; . . . and t = 12 to refer to the observation in quarter 4 of year 3. Using the dummy variables defined in part (b) and t develop an equation to account for seasonal effects and any linear trend in the time series. Based upon the seasonal effects in the data and linear trend, compute the quarterly forecasts for nextyear.
Step by Step Answer:
An Introduction To Management Science Quantitative Approaches To Decision Making
ISBN: 226
13th Edition
Authors: David Anderson, Dennis Sweeney, Thomas Williams, Jeffrey Cam