12.54 John Swanson, president of Market Research Inc., has asked you to estimate the coefficients of the model Y = b0 + b1X1 + b2X21

+ b3X2 where Y is the expected sales of office supplies for a large retail distributor of office supplies, X1 is the total disposable income of residents within 5 miles of the store, and X2 is the total number of persons employed in information-based businesses within 5 miles of the store. Recent work by a national consulting firm has concluded that the coefficients in the model must have the following restriction:

b1 + b2 = 2 Describe how you would estimate the model coefficients using least squares.