The Sensitivity of Common Capability Indices to Departures from Normality
The process capability index Cpw provides a general representation for a wide variety of process capability indices including Cp, Cpk, Cpm and Cpmk. In this manuscript we will develop a procedure to investigate the sensitivity of Cpw to departures from normality and discuss the impact on inferences drawn for a variety of regions and weights. The focus will be on the widely used indices and in particular those indices whose inference focuses on the ability of the process to be clustered around the target. The robustness of Ĉpw to distributional assumptions and the resulting impact on the inferences will be compared.
KeywordsBreaking Strength Process Capability Customer Requirement Total Quality Management Capability Index
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