基于测量误差的过程能力指数的统计分析

Statistical Analysis of Process Capability Indices Based on Measurement Errors

针对许多围绕过程能力指数估计量统计性质的研究不考虑测量误差的问题,在考虑测量误差的情况下,给出了过程能力指数的统计性质。研究结果表明:抽样误差会导致高估过程能力,测量误差会导致低估过程能力,抽样误差与测量误差对过程能力指数的联合影响所造成的偏倚有正有负,这取决于两者对过程能力指数的影响程度。

Measurement errors have not been taken into consideration in most researches on the statistical properties of PCIs.The statistical properties of PCIs with the presence of measurement errors were presented.The results show that the sampling errors will lead to overestimating the process capability,while the measurement errors will lead to underestimating the process capability.The combination of the two effects involves the bias which can be either positive or negative values,depending on their effect on the index of process capability.