ESTIMATING PROCESS CAPABILITY INDEXES FOR NONNORMAL PEARSONIAN POPULATIONS

Abstract

Clements(1) introduced a method for calculating the estimators of two classical process capability indices (PCI), C-p and Cpk, for non-normal Pearsonian populations. Pearn and Kotz(2) applied Clements' method to obtain first approximation estimators of PCIs for non-normal populations to the two more advanced PCIs, C-pm and C-pmk developed by Chan et al.(3) and Pearn ct al.(4) In this paper, we consider a different approach for calculating the estimators of the four PCIs. The new approach may be viewed as a modification of Clements' method. Comparisons between Clements' and the proposed new methods are also provided.