SChart Class

SChart is an S chart using sample standard deviations to monitor the variability of a process. This is normally used with sample sizes greater than 10.

For a list of all members of this type, see SChart Members.

System.Object
   Imsl.Chart2D.AbstractChartNode
      Imsl.Chart2D.ChartNode
         Imsl.Chart2D.Data
            Imsl.Chart2D.QC.ShewhartControlChart
               Imsl.Chart2D.QC.SChart

public class SChart : ShewhartControlChart

Thread Safety

Public static (Shared in Visual Basic) members of this type are safe for multithreaded operations. Instance members are not guaranteed to be thread-safe.

Remarks

The control limits are at

$\bar{s} + k \frac{\bar{s}}{c_{4,n}}\sqrt{1-c_{4,n}^2}$

where $\bar{s}$ is the mean of the within sample standard deviations, n is the sample size, and k is the value of the "ControlLimit" attribute for the line. Additionally,

$c_{4,n}=\sqrt{\frac{2}{n-1}}\frac{\Gamma(\frac{n}{2})}{\Gamma(\frac{n-1}{2})}$

is a factor such that $\bar{s}/c_{4,n}$ is an unbiased estimator of the within sample standard deviation. By default, the chart contains an upper control limit line with k=3, a lower control limit line with k=-3, and a central line equal to $\bar{s}$ . Additional control limit lines can be added. The method AddWeco adds control limits with k = -2, -1, 1, 2.

Requirements

Namespace: Imsl.Chart2D.QC

Assembly: ImslCS (in ImslCS.dll)

SChart Class

Thread Safety

Remarks

Requirements

See Also