Glossary
Method of Least Squares: A method of finding a line of "best fit" to a set of data by minimizing the sum of the errors (also called the residuals). Other methods exist to find a line of "best fit" based on different criteria, such as the method of least absolute deviations.
Least Squares Regression Line: The line of best fit resulting from using the method of least squares.
Error or Residual: The vertical deviation between a data point and a fitted line.
SSE: Sum of Squared Errors, or the sum of all of the squared residuals.