Least Squares Regression Line

Correlation is closely related to Least Squares Regression. Why is it called the Least Squares Regression? Drag the two "Drag Me!" points to fit a line of best fit between the points this should be when the sum of the squares of the residuals is as small as possible. Once you are satisfied that you can not make the sum of squares any smaller, click on the check box to see the true regression line.