关于非正态总体的工序能力指数Cp值计算的研究

就化工等行业中普遍存在的产品质量稳定而工序能力指数偏低的问题,进行了较为深入的研究.研究表明,上述问题是由于工序产品的质量指标X在局部范围内不服从正态分布所导致,进而指出了现行的工序能力指数的计算方法在某些行业(如化工等行业)的不适用性.根据该研究结果,当产品质量指标X在服从上述非正态分布时,依据数理统计的基本原理,在导致第一类错误发生的概率不大于0.27%的前提下,重新定义工序能力指数的计算公式即可以有效地解决上述问题.

Research on computing the value of the work procedure ability index Cp

This thesis aims at an in-depth research of the phenomenon-steadiness in product quality but low index of work procedure ability, which generally exists in such fields as chemical industry. The research proves that the above-mentioned problem results form the fact that the quality index of work procedure products X is not subordinate to the normal distribution in parts of an area. And it further proves that the current calculating method of work procedure ability index is unadaptable in some areas such as chemical industry. According to the research result of the thesis, it can be concluded that redefining the calculating formula of work procedure ability index may lead to an effective solution of the above problem, with the quality index of work procedure products X subordinate to the above abnormal distribution, mathematical statistics as fundamental principle, and the probability leading to the first-class error less than 0.27%.