Box-cox transformation approach for evaluating non-normal processes capability based on the Cpk index

Chia-Huang Wu*, S. J. Lin, D. L. Yang, W.l. Pearn

*Corresponding author for this work

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

In manufacturing quality control and operations management, the process yield plays an important role. The capability index Cpk provides a lower bound on the process yield under the assumption that the process characteristic is normally distributed. When the normality assumption is violated, we can transform the non-normal data into normal data by using an appropriate transformation approach. In this paper, we consider the Box-Cox transformation and compare two estimation methods including the maximum likelihood estimator (MLE) and the method of percentiles (MOP). The performance comparison is based on the coverage rate, the precision, and the accuracy of the process non-conformity percentage evaluation. For various sample sizes and various distributions, several figures are presented to compare these two methods.

Original languageEnglish
JournalJournal of Testing and Evaluation
Volume42
Issue number4
DOIs
StatePublished - 1 Jan 2014

Keywords

  • Box-Cox transformation
  • Coverage rate
  • Non-normal distribution

Fingerprint Dive into the research topics of 'Box-cox transformation approach for evaluating non-normal processes capability based on the C<sub>pk</sub> index'. Together they form a unique fingerprint.

  • Cite this