Fraction of Design Space Plots for Assessing Mixture and Mixture-Process Designs

Abstract

Variance dispersion graphs are useful tools for evaluating various types of designs, including mixture and mixture-process designs. They allow an experimenter to see patterns of scaled prediction variances (SPV) throughout a design space. We introduce a complementary fraction of design space (FDS) plot that provides additional information on the distribution of the SPV throughout a design space. These plots display the fraction of design space where the SPV is less than or equal to specific values. The FDS plots for combined mixture-process experiments also show which of the two types of variables has more influence on the SPV. The FDS plots for mixture and mixture-process experiments are developed and then demonstrated with several examples.

• Fraction of Design Space Plot
• Mixture Experiments
• Scaled Prediction Variance
• Variance Dispersion Graphs

Additional information

Notes on contributors

Heidi B. Goldfarb

Dr. Goldfarb is a Principal Statistician in the Research and Development Department. She is a Member of ASQ. Her e-mail address is [email protected].

Christine M. Anderson-Cook

Dr. Anderson-Cook is an Associate Professor in the Department of Statistics. She is a Member of ASQ. Her e-mail address is [email protected].

Connie M. Borror

Dr. Borror is a Assistant Professor in the Department of Decision Sciences. She is a Senior Member of ASQ. Her e-mail address is [email protected].

Douglas C. Montgomery

Dr. Montgomery is a Professor in the Department of Industrial Engineering. He is a Fellow of ASQ. His e-mail address is [email protected].