Second, it’s the line that allows us our best guess (at estimating what college GPA would be, given each high school GPA). For example, if high school GPA is 3.0, then college GPA should be around (remember, this is only an eyeball prediction) 2.8. Take a look at Figure 16.3 to see how we did this. We located the predictor value (3.0) on the x-axis, drew a perpendicular line from the x-axis to the regression line, then drew a horizontal line to the y-axis, and finally estimated what the predicted value of Y would be.
