THE SELECTION OF TERMS IN RESPONSE-SURFACE MODELS - HOW STRONG IS THEWEAK-HEREDITY PRINCIPLE

Model selection under the weak-heredity principle allows models that c ontain compound terms such as x(1)x(2) to have only one of the corresp onding x(1) and x(2) terms in the model. It is shown that the conditio ns required to justify use of the principle are so restrictive as to m ake it unusable in practice. An example is given to illustrate this.