BAYESIAN ESTIMATIONS OF SOME PROCESS CAPABILITY INDICES UNDER RESTRICTIVE ASSUMPTIONS

ABSTRACT

Capability indices, such as, C_p, C_pk, C_pm and C_pmk , are important quantities to provide a measure of process potentiality and performance. In this paper we consider the problem of estimations of indices C_pm (µ T) and C_pmk (µ = m) under Bayesian framework. Several priors such as non-informative, conjugate prior and Weibull hazard function have been considered. Some estimates of hyper parameters are also studied. Some Bayesian estimators are derived and lower bounds of the credible intervals under some conditions are also given.

Keywords:

• process capability indices
• Bayesian approach
• credible interval
• non-informative prior
• conjugate prior