| Summary: | 碩士 === 國立交通大學 === 工業工程與管理系所 === 92 === The process capability indices（PCIs）are widely used to evaluate a manufacturer’s general process capability. PCIs are generally defined as the ratio of the allowable tolerance of a quality characteristic to the actual process performance. Furthermore, the quality of many products is usually determined by more than one characteristic. Univariate indices are not adequate for assessing the capability of processes with multiple characteristics. Among all developed multivariate process capabilities, index has the most accurate estimation of Cpm. takes into account both the ratio of the tolerance region to the process region and the probability of nonconforming product. However, the exact probability distribution of is too complicated to be derived. Consequently, the related hypothesis testing and confidence interval cannot be developed. The main objective of this study is to utilize Bootstrap simulation method to construct confidence interval for the difference of two process capability indices, Cpm1 - Cpm2. The proposed Bootstrap interval for Cpm1-Cpm2 can be effectively utilized to compare two multivariate processes. A simplified procedure of constructing the confidence interval for Cpm1 -Cpm2 is also provided by this study for engineers without much Statistics background.
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