The sub-prime mortgage crisis that hit the world economy also affected the real estate market. Both new and existing home sales were affected. A file titled EHSales contains the number of existing homes sold

(in millions) from September 2007 to September 2008.

a. Construct a line plot for these data.

b. The data file also contains data concerning the median selling price ($thousands). Construct a graph containing the line plot for both the number of sales (millions) and the median price of these sales for the indicated time period.

c. Describe the relationship between the two line plots constructed in part b.