ENBIS: European Network for Business and Industrial Statistics

Graphical Selection of Effects in General Factorials

Abstract

Submitted by

Pat Whitcomb

Authors

Pat Whitcomb Gary W. Oehlert

Affiliation

Stat-Ease, Inc. & School of Statistics, University of Minnesota

Abstract

Many design of experiment practitioners are familiar with the half-normal plot introduced by Cuthbert Daniel (1959) to select model terms in the standard two-level factorial (2^k-p series) designs. We show an extension to the Daniel plot of effects that permits factors with more than two levels. Advantages of half-normal plot are: it is less intimidating than numerical methods, it is easy to understand and it provides a degree of protection against multiple testing.

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