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Is Your Process on Its Best Behavior?
- Article from:
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ASQ Six Sigma Forum Magazine
- Article date:
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August 1, 2005
- Author:
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Copyright informationCopyright American Society for Quality Aug 2005. Provided by ProQuest LLC. (Hide copyright information)
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USE TRENDED PROCESS BEHAVIOR CHARTS TO VERIFY PROCESS STABILITY.
Most Six Sigma practitioners are taught to beware trends and seasonality effects when viewing data in a time series. When processes are plotted in time order, the appearance of runs, trends and cycles is evidence of memory.
One way to deal with correlations is to widen the time between the observations. Then statistical tools that don't assume correlations may be used for prediction and control. Six Sigma practitioners are often advised to use time series methods when correlations are natural to the process and sampling frequency cannot be reduced.
In a recent article, Joseph D. Conklin discussed time series modeling using a ...