Home values tend to increase over time under normal conditions, but the recession of 2008 and 2009 has reportedly caused the sales price of existing homes to fall nationwide (BusinessWeek, March 9, 2009). You would like to see if the data support this conclusion. The file HomePrices contains data on 30 existing home sales in 2006 and 40 existing home sales in 2009. Click on the datafile logo to reference the data.
a. Provide a point estimate of the difference between the population mean prices for the two years.
b. Develop a 99% confidence interval estimate of the difference between the resale prices of houses in 2006 and 2009.
c. Would you feel justified in concluding that resale prices of existing homes have declined from 2006 to 2009? Why or why not?