As an intern with the local home builder's association, you have been asked to analyze the state of the local housing market, which has suffered during a recent economic crisis. You have been provided two data sets: the Pre-Crisis data contains information on 1,978 single-family homes sold during the one-year period before the burst of the "housing bubble," and the Post-Crisis data contains information on 1,657 single-family homes sold during the one-year period after the burst of the housing bubble. In addition, there is a set of 2,000 observations designated as a test set corresponding to homes currently for sale. Because the homes in the test set have not yet been sold, each of these 2,000 observations has an artificial value of zero for the sale price.