Measures of Lack of Fit, and Transformation of Predictors in Composite Designs.

Abstract : The central composite designs are investigated in terms of their ability to detect lack of fit and it is shown that measures of non-quadraticity can be obtained in all the k major directions. The geometrical interpretation of this is explained. The relationship of these lack of fit measures to the estimation of power transformations in the predictor variables is also explored. (Author)