R 2 (R-squared) is a statistical measure of the goodness of fit of a linear regression model (from 0.00 to 1.00), also known as the coefficient of determination.

In this article, you'll learn the basics of simple linear regression, sometimes called 'ordinary least squares' or OLS regression —a tool commonly used in forecasting and financial analysis.

Figure 1: The results of multiple linear regression depend on the correlation of the predictors, as measured here by the Pearson correlation coefficient r (ref. 2).

The National Council on Measurement in Education (NCME) is a professional organization for individuals involved in assessment, evaluation, testing, and other aspects of educational measurement.

Michael P. Jones, Indicator and Stratification Methods for Missing Explanatory Variables in Multiple Linear Regression, Journal of the American Statistical Association, Vol. 91, No. 433 (Mar., 1996), ...