XbarR is an X-bar chart for monitoring a process using sample ranges.

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

Syntax

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

Remarks

The control limits are at

\bar{\bar x} + k \frac{\bar{R}}{d_{2,n}\sqrt{n}}
where \bar{\bar{x}} is the grand mean of all of the observations, \bar{R} is the mean of the observed ranges, n is the sample size, and k is the value of the "ControlLimit" attribute for the limit. Additionally, d_{2,n}=E[R]/\sigma, where R is the range of data from a Gaussian distribution. Therefore \bar{R}/d_{2,n} is an estimate of the within sample standard deviation.

By default, the chart contains an upper control limit with k=3, a lower control limit with k=-3, and a central line equal to \bar{\bar{x}}. Additional control limits can be added. The method AddWeco adds control limits with k = -2, -1, 1, 2.

Inheritance Hierarchy

See Also