Control limit: Difference between revisions
wikademia>Jayen466 Not to be confused with tolerance limits |
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For [[normal distribution|normally distributed]] statistics, the area bracketed by the control limits will on average contain 99.73% of all the plot points on the chart, as long as the process is and remains in statistical control. | For [[normal distribution|normally distributed]] statistics, the area bracketed by the control limits will on average contain 99.73% of all the plot points on the chart, as long as the process is and remains in statistical control. | ||
Control limits should not be confused with | Control limits should not be confused with ''tolerance limits'', which are completely independent of the [[distribution]] of the plotted sample statistic. | ||
[[Category:Statistics]] | [[Category:Statistics]] | ||
Revision as of 19:23, 29 June 2007
Control limits are horizontal lines drawn on an SPC control chart, usually at a distance of ±3 standard deviations from the mean of the plotted statistic.
For normally distributed statistics, the area bracketed by the control limits will on average contain 99.73% of all the plot points on the chart, as long as the process is and remains in statistical control.
Control limits should not be confused with tolerance limits, which are completely independent of the distribution of the plotted sample statistic.