3.6 Assessing the Accuracy of the Model

• RSE can be considered a measure of the lack of fit of the model. a
• \(R^2\) statistic provides an alternative that is in the form of a proportion of the variance explained, ranges from 0 to 1, a good value depends on teh application.

\[R^2 = 1 - \frac{RSS}{TSS}\] where TSS is the total sum of squarse: \[TSS = \Sigma (y_i - \bar{y})^2\]