Application of Analysis of Means (ANOM) to Nested Designs for Improving the Visualization and Understanding of the Sources of Variation of Chemical and Pharmaceutical Processes

Abstract

A case study, in the chemical and pharmaceutical industry, is used to show the value of the application of analysis of means (ANOM) as a powerful visualization and communication tool, to complement the conventional analysis of nested designs. In addition, by focusing the interpretation of ANOM charts on the patterns of the means rather than on the individual differences among the means, it is shown that ANOM charts could be useful in detecting relations among the nested factors that may be the key in resolving quality problems.

Keywords:

• Design of experiments
• Nested designs
• Analysis of means
• Validation
• Chemical and pharmaceutical processes

Acknowledgments

The authors wish to thank Dr. Donald J. Wheeler for his valuable advices and Patricia Andrew and Alma Garduño for the help in preparing the final manuscript.