CChart Class

CChart is a c-chart for monitoring the count of the number of defects when defects are rare. Control limits are computed using the Poisson distribution. If defects are not rare NpChart should be used instead.

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

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

public class CChart : 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

$\bar{c}+k\sqrt{\bar{c}}$

where $\bar{c}$ is the mean number of defects per sample and k is the value of the "ControlLimit" attribute for the line.

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 $\bar{c}$ . Additional control limits can be added. The method AddWeco adds control limits with k = -2, -1, 1, 2.

The lower control limit is computed using the Poisson distribution. First the probability of the number of defects being less than k (the "ControlLimit" value) standard deviations from the mean in a normal distribution is computed. The number of defects required to produce the same probability assuming a Poisson distribution, with the same mean, is then computed. The lower limit is set to be one more than this number of defects.

Requirements

Namespace: Imsl.Chart2D.QC

Assembly: ImslCS (in ImslCS.dll)

CChart Class

Thread Safety

Remarks

Requirements

See Also