Quarterly Sales Data (In $10,000) for a Small Company Specializing

Essay

Quarterly sales data (in $10,000) for a small company specializing in green cleaning products are shown in the time series graph below. A seasonal regression model was fit to these data and the results are shown below.
The regression equation is Sales = 89.06 + 1.37t - 23.37Q2 - 23.91Q3 + 27.88Q4. a. Is the seasonal regression model significant overall? Explain.
b. Interpret the regression coefficients in this model.
c. Use this model to provide forecasts for each of the four quarters of the next year.