Confidence Intervals for Variance Components in Measurement System Capability Studies

Abstract

In Measurement System Analysis a relevant issue is how to find confidence intervals for the parameters used to evaluate the capability of a gauge. In literature approximate solutions are available but they produce so wide intervals that they are often not effective in the decision process. In this article we introduce a new approach and, with particular reference to the parameter γ_R, i.e., the ratio of the variance due to the process and the variance due to the instrument, we show that, under quite realistic assumptions, we obtain confidence intervals narrower than other methods. An application to a real microelectronic case study is reported.

Keywords:

• Confidence coefficient
• Generalized confidence interval
• Modified large sample
• Repeatability and reproducibility

Mathematics Subject Classification:

• 62 F
• 62 K

Acknowledgments

The authors wish to thank the guest editor and the referees for their thoughtful and detailed suggestions that improved the final version of this article.