Qd = 5,000 - 15P + 50A + 3Px - 4I,
(2, 117) (2.7) (15) (2) (3)

where Qd = Quantity Demanded, P = Good Price, A = Advertising Expenditures, Px = Price of a Competitive Good, A = Advertising Expenditures, I = Average Monthly Income, and the Standard Errors of the Regression Coefficients are shown in Parentheses.
Compute the t-statistics for each variable and explain what is inferences can be drawn from them. If R2 of this equation is 0.25, what inference can be drawn from it.