A short note on the effect of sample size on the estimation error in Cp |
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| Authors: | Zahra Sedighi Maman W Wade Murphy Saeed Maghsoodloo Fatemah Haji Ahmadi |
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| Affiliation: | 1. Department of Industrial and Systems Engineering, Auburn University, Auburn, Alabama;2. Department of Industrial Engineering, Iran University of Science and Technology, Tehran, Iran |
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| Abstract: | Process capability indices such as Cp are used extensively in manufacturing industries to assess processes in order to decide about purchasing. In practice, the parameter for calculating Cp is rarely known and is frequently replaced with estimates from an in-control reference sample. This article explores the optimal sample size required to achieve a desired error of estimation using absolute percentage error of different Cp estimates. Moreover, some practical tools are created to allow practitioners to find sample size in different situations. |
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| Keywords: | absolute percentage error Phase I process capability six sigma standard deviation |
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