Rhonda Clark, a Slippery Rock, Pennsylvania, real estate developer, has devised a regression model to help determine residential housing prices in northwestern Pennsylvania. The model was developed using recent sales in a particular neighbor-hood. The price (Y) of the house is based on the size ( square foot-age 5 X) of the house. The model is:

Y = 13,473 + 37.65X

The coefficient of correlation for the model is 0.63.

a) Use the model to predict the selling price of a house that is 1,860 square feet.

b) An 1,860- square- foot house recently sold for $ 95,000. Explain why this is not what the model predicted.

c) If you were going to use multiple regressions to develop such a model, what other quantitative variables might you include?

d) What is the value of the coefficient of determination in this problem?