The Coefficient of Determination: Understanding r squared and R squared

Abstract

Fitting least-squares lines to bivariate data is a topic traditionally discussed in introductory statistics courses, often in a unit of study that includes correlation. Recently, because calculators that graph bivariate data sets and compute regression equations have become widely available, this topic has also been included in many algebra and precalculus courses. After students learn about linear models, additional discussions may concern transforming data to achieve linearity so that students can find models of other functional forms. They can also use calculators or computers to fit curves without going through the reexpression process; this procedure would be more common in algebra or precalculus than in statistics classes.