5.12 Death by Intent. Return to the data of Exercise 5.5 (page 134) on homicide rate and suicide rate. We will use these data to illustrate influence. DEATH4

(a) Make a scatterplot of the data that are suitable for predicting suicide rate from homicide rate, with two new points added. Point A: homicide rate 10.8, suicide rate 27.0. Point B: homicide rate 18.0, suicide rate 14.0. In which direction is each of these points an outlier?

(b) Add three least-squares regression lines to your plot: for the original 26 counties, for the original 26 counties plus Point A, and for the original 26 counties plus Point B. Which new point is more influential for the regression line? Explain in simple language why each new point moves the line in the way your graph shows.