Refer to the residential sales data in Problem 19 in Chapter 12. Use the computer output given below to answer the following questions.
a. State an ANACOVA regression model that can be used to compare outer suburbs with other locations (intown and inner suburbs), controlling for age.
b. Identify the model that should be used to check whether the ANACOVA model in part (a) is appropriate. Carry out the appropriate test.
c. Using ANACOVA, determine adjusted mean sales prices for the two locations, and test whether they differ significantly from one another. (Mean house age = 10.8667; unadjusted mean sales price (in $l,000s) for intown and inner suburbs = 82.1867; unadjusted mean sales price (in $ 1,000s) for outer location = 84.8067.)
Regression of Sales Price (Y) on Age (X4), Location (Z), and X4 × Z

Regression of Sales Price (Y) on Age (X4), Location (Z), and X4 × Z
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