Chapter 1, Problem 1.25ACI

Zillow.com estimates of home values. Zillow.com is a real estate Web site that provides free estimates of the market value of homes. A trio of University of Texas at San Antonio professors compared Zillow estimates to actual sale prices of homes and published their results in The Appraisal Journal (Winter 2010). The analysis was based on data collected for 2,045 single-family residential properties in Arlington, Texas, that sold during the last 6 months of 2006. Sale price and Zillow estimated value (in dollars) were measured for each property. Zillow claims that this market has one of its highest-accuracy ratings. However, the research revealed that Zillow overestimated the market value by more than 10% for nearly half of the properties.

1. a. What is the experimental unit for this study?
2. b. Describe the variables measured in the study. Do these variables produce quantitative or qualitative data?
3. c. Give a scenario where the 2,045 properties represent a population.
4. d. If the 2,045 properties represent a representative sample from a population, describe the population.
5. e. Suppose the relevant population is all single-family residential properties in the United States. Do you believe the 2,045 properties are representative of this population? Explain.