Your scatterplot in Exercise 10.34 shows one unusual point: Student 3, who drank nine beers.
bac
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 direction so that it may be influential?
Do the regression again, omitting Student 3. Add the new regression line to your scatterplot. Does removing this observation greatly change predicted BAC? Does change greatly? Does the -value of your test change greatly? What do you conclude: did your work in the previous problem depend heavily on this one student?