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 between the horizontal variable and the vertical variable . Create three similar scatterplots again, after clicking the “Show least-squares line” box to display the regression line. Correlation is considered reasonably strong in many areas of work. Because there is a reasonably strong correlation, we might use a regression line to predict from . In which of your three scatterplots does it make sense to use a straight line for prediction?