Process capability indices for data following the Poisson or binomial distribution

Abstract

Process capability indices are widely used for the characterization of the capability of a process. The literature on process capability indices for discrete data is rather limited. In this paper, we propose transformation techniques for Poisson and binomial data. The transformed data are approximately independent and normally distributed. Therefore, the practitioner is able to compute the usual process capability indices without defining new indices which are not always easy to interpret.

Keywords:

• Binomial distribution
• Poisson distribution
• process capability indices
• Q statistics
• quality control

Acknowledgements

The author would like to thank the referee for helpful comments and suggestions that improved the paper.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Notes on contribuor

Petros Maravelakis, is Assistant Professor in the Department of Business Administration at the University of Piraeus, Greece. His fields of interest are control charts, process capability indices and reliability.