Drag the red point labeled "Drag Me." As this point moves, the sum of the squared residual errors changes,
becoming minimum as the line [math]y = \bar{y}[/math] is rotated onto the Least Squares Regression Line.
The percentage decrease in the sum of the squared residual errors between the line [math]y = \bar{y}[/math]
and the Least Squares Regression Line is the value of [math]R^2[/math] (as a percentage).
