A new graphical method for assessing parametric transformations of the response in linear regression is given. We simply regress the response variable Y on the predictors, find the fitted values, and then dynamically plot the transformed response Y(λ) against those fitted values by varying the transformation parameter λ until the plot is linear. The method can be used also to assess the success of numerical response transformation methods and to discover influential observations. Modifications using robust estimators can be used as well.
Bibliographical noteFunding Information:
We thank the referees, the associate editor, and the editor for helpful comments. This work was supported in part by National Science Foundation grants DMS-9703777 and DMS-0103983.
- Box-Cox transformation