Journal of Applied Sciences

Year: 2006 | Volume: 6 | Issue: 12 | Page No.: 2676-2678
DOI: 10.3923/jas.2006.2676.2678

Effect of Scale Parameters in the Performance of Shewhart Control Chart with Interpretation Rules

Abdul Sattar Jamali, Li Jin Lin and Dai Yingzhuo

Abstract: It is common in practice that the Shewhart chart usually supplemented with interpretation rules in order to detect the small shifts in the process mean. In this study the effect of scale parameters in the performance of the Shewhart control chart of the most used seven interpretation rules were obtained through by developing a spread sheet for normal and gamma distributions when process remains in control. The results show that the in-control performance can be fairly high for particular rules when the underlying data from a gamma distribution rather than normal distribution considering scale parameters. It was also observed that the in-control performance of gamma distribution grows larger when the scale parameter increases.

Keywords: scale parameter, Shewhart control chart, Interpretation rules, normal distribution and gamma distribution

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