XmR is an XmR chart for monitoring a process using moving ranges.

Namespace: Imsl.Chart2D.QC
Assembly: ImslCS (in ImslCS.dll) Version: 6.5.0.0

Syntax

C#
[SerializableAttribute]
public class XmR : ShewhartControlChart
Visual Basic (Declaration)
<SerializableAttribute> _
Public Class XmR _
	Inherits ShewhartControlChart
Visual C++
[SerializableAttribute]
public ref class XmR : public ShewhartControlChart

Remarks

The moving range control chart uses the moving range of two successive observations to measure the process variability. This control chart is used for individual measurements (sample size = 1).

The moving range is defined to be \mathrm{MR}_i=|x_i-x_{i-1}|.

The control limits are at

\bar{x}+k\frac{\overline{MR}}{d_{2,2}}
where \bar{x} is the mean of all of the individual observations, \overline{MR} is the mean of the moving averages, and k is the value of the "ControlLimit" attribute for the line. Additionally, d_{2,n}=E(R)/\sigma where R is the range of a Gaussian distribution. Therefore \overline{MR}/d_{2,2} is an estimate of the 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{x}. Additionally control limits can be added. The method AddWeco adds control limits with k = -2, -1, 1, 2.

Inheritance Hierarchy

See Also