2.49 Is regression useful?

In Exercise 2.39 (pages 79–80), you used the Correlation and Regression applet to create three scatterplots having correlation about r = 0.7 between the horizontal variable x and the vertical variable y. Create three similar scatterplots again, after clicking the “Show least-squares line” box to display the regression line.Correlation r = 0.7 is considered reasonably strong in many areas of work. Because there is a reasonably strong correlation, wemight use a regression line to predict y from x. In which of your three scatterplots does it make sense to use a straightline for prediction?

89