To do these exercises, go to www.macmillanhighered.com/fapp10e.

Question 6.96

1. In the Correlation and Regression applet, imitate Figure 6.16 (page 269). Click to locate five points at the lower left of the scatterplot, and then click “Show least- squares line.”

  1. What is the correlation for these five points? If necessary, move points with the mouse to get a value near , as in Example 9 (page 268).
  2. Now add an outlier at the upper right that lies exactly on the line. What is the correlation for the six points?
  3. Use the mouse to drag the outlier down and then to the left. Watch the least-squares line follow this one point. How negative can you make the correlation ?
  4. What have you learned from parts (a) through (c) about the effect that a single outlier can have on the correlation ?