I need to understand the formula so I can get to the answer of this equation.

IBEX has hired you to analyze demand in 25 regional markets for a new Product Y, called Angelica Pickles. A statistical analysis of the demand in these markets shows (standard errors in parentheses):

Q_Y= 250 - 10P + 6PX + 0.25A + 0.04I

(100)(3) (2) (0.1)(0.15)

R²= 90%

Standard Error of the Estimate = 75

Here, Q_Yis the market demand for Product Y, P is the price of Y in dollars, A is dollars of advertising expenditures, P_Xis the average price in dollars of another (unidentified) product, and I is dollars of household income. In a typical market, the price of Y is $1,500, P_Xis $500, advertising expenditures are $50,000, and disposable income per household is $45,000. The numbers in parentheses are standard errors of the coefficients. Based on this information, do the following:

a.Calculate the expected level of demand for Y.

b.Indicate the range within which actual demand is expected to fall with 95% confidence.

c.Interpret R².

d.Test the significance of Advertising (A), at = 0.05.