SSerr (the sum of squared predictions errors, equivalently the residual sum of squares), SStot (the total sum of squares), and SSreg (the sum of squares of the regression, equivalently the explained sum of squares) are given by
SSerr (sum of squared prediction errors, equivalent to the residual sum of squares), SStot (total sum of squares), and SSreg (sum of squares of the regression, equivalent to the explained sum of squares) represent the same statistical measures.