Influence? Your scatterplot in Exercise 10.31 shows one house whose selling price is quite high for its size. Rerun the analysis without this outlier. Does this one house influence r2, the location of the least-squares line, or the t statistic for the slope in a way that would change your conclusions? HSIZE 10.36 Influence? Your scatterplot in Exercise 10.34 shows one unusual point: Student 3, who drank nine beers. BAC

(a) Does Student 3 have the largest residual from the fitted line? (You can use the scatterplot to see this.) Is this observation extreme in the x direction so that it may be influential?

(b) Do the regression again, omitting Student 3. Add the new regression line to your scatterplot. Does removing this observation greatly change predicted BAC? Does r2 change greatly? Does the P-value of your test change greatly? What do you conclude: did your work in the previous problem depend heavily on this one student?