The data contains the selling price, squarefootage, and the age of houses that were recently sold. In addtion, we use 1 to indicate if the house has a garage, 0 otherwise. Do a regession analysis to answer the following problems:
a) What is the impact of the garage on the selling price?
b) Does the garage have any effect on the squarefootage's impact on selling price? If so, how?