Six Sigma for Organizational Excellence pp 49-65 | Cite as
Understanding Variation
Abstract
Variation is inherent in any process-based project. Hence, the ultimate aim of a Six Sigma project is to eliminate variation and waste through continuous improvement. The main two sources of variation are the assignable causes of variation and the random or common causes of variation. The assignable causes of variations are the result of physical in nature, can result through man, machine, materials, management, methods, procedures, etc., and are generally able to control and eliminate. The random causes of variation are generally an effect of environment and situation specific, and therefore, eliminating complete variation from a process is impossible. The chapter also discusses the necessity of measuring variation and the importance of having a good measurement system in place. The importance of normal distribution in statistical study is emphasized from the process variation point of view. Various measures of variation are also studied to support the understanding of the basics of a processed data.
Keywords
Accuracy Repeatability Reproducibility Stability Resolution Linearity Range Quartile deviation Skewness Kurtosis Coefficient of variation CorrelationReferences
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