control chart

statistics

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June 24, 2026

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A control chart is a graphical display used in statistical process control to monitor the quality of an ongoing process. It helps determine if variations in output are due to random, common causes or identifiable, assignable causes.12

Control charts are constructed with a center line representing the process mean and upper and lower control limits, typically set at three standard deviations from the mean. When sample data points fall within these limits, the process is considered in control. If a point falls outside the limits, it signals the need for adjustment to maintain acceptable quality. Different types of control charts exist, such as x̄-charts for sample means and p-charts for defect proportions.12

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statistics
Statistical process control
…display referred to as a control chart provides a basis for deciding whether the variation in the output of a process is due to common causes (randomly occurring variations) or to out-of-the-ordinary assignable causes. Whenever assignable causes are identified, a decision can be made to adjust the process in order…
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…display referred to as a control chart provides a basis for deciding whether the variation in the output of a process is due to common causes (randomly occurring variations) or to out-of-the-ordinary assignable causes. Whenever assignable causes are identified, a decision can be made to adjust the process in order…
Read More