A real estate agent is trying to understand the pricing of homes in her area, a region in the United States comprising small to midsize towns and a small city. For each of 1200 homes recently sold in the region, the file ch13_MCSP_Real_Estate holds the following variables:

• Sale Price (in $)

• Lot Size (size of the lot in acres)

• Waterfront (Yes, No)

• Age (in years)

• Central Air (Yes, No)

• Fuel Type (Wood, Oil, Gas, Electric, Propane, Solar, Other)

• Condition (1 to 5; 1 5 Poor, 5 5 Excellent)

• Living Area (in square feet)

• Pct College (% in zip code who attend a four-year college)

• Full Baths (number of full bathrooms)

• Half Baths (number of half bathrooms)

• Bedrooms (number of bedrooms)

• Fireplaces (number of fireplaces) 

The agent has a family interested in a four-bedroom house. Using confidence intervals, how should she advise the family on what the average price of a four-bedroom house might be in this area? Compare that with a confidence interval for two-bedroom homes. How does the presence of central air conditioning affect the mean price of houses in this area? Use confidence intervals and graphics to help answer that question. Craig Hanson