Consider the Following Set of Quarterly Sales Data Given in Thousands

Essay

Consider the following set of quarterly sales data given in thousands of dollars. The following dummy variable model that incorporates a linear trend and constant seasonal variation was used: y (t)= B₀ + B_1t + B_Q1(Q1)+ B_Q2(Q2)+ B_Q3(Q3)+ E_t
In this model there are 3 binary seasonal variables (Q1,Q₂,and Q₃).
Where
Q_i is a binary (0,1)variable defined as:
Q_i = 1,if the time series data is associated with quarter i;
Q_i = 0,if the time series data is not associated with quarter i.
The results associated with this data and model are given in the following MINITAB computer output.
The regression equation is
Sales = 2442 + 6.2 Time - 693 Q1 - 1499 Q2 + 153 Q3 Provide a managerial interpretation of the regression coefficient for the variable "time."