Chapter 12.4, Problem 44PB

Predicting house prices The House Selling Prices FL data file on the book’s website has several predictors of house selling prices. The table here shows the ANOVA table for a regression analysis of y = the selling price (in thousands of dollars) and x = the size of house (in thousands of square feet). The prediction equation is $\hat{y}=9.2+77x$.

ANOVA table for selling price and size of house:

1. a. What was the sample size? (Hint: You can figure it out from the residual df.)
2. b. The sample mean house size was 1.53 thousand square feet. What was the sample mean selling price? (Hint: What does $\hat{y}$ equal when x = x̄?)
3. c. Estimate the standard deviation of the selling prices for homes that have x = 1.53. Interpret.
4. d. Report an approximate prediction interval within which you would expect about 95% of the selling prices to fall for homes of size x = 1.53.