Returns the capability index $c_{pk}$ .

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

Syntax

C#
public virtual double CapabilityIndexCpk( double lowerSpecificationLimit, double upperSpecificationLimit )

Visual Basic (Declaration)
Public Overridable Function CapabilityIndexCpk ( _ lowerSpecificationLimit As Double, _ upperSpecificationLimit As Double _ ) As Double

Visual C++
public: virtual double CapabilityIndexCpk( double lowerSpecificationLimit, double upperSpecificationLimit )

lowerSpecificationLimit: Type: System..::.Double
The lower specification limit.

upperSpecificationLimit: Type: System..::.Double
The upper specification limit.

The capability index $c_{pk}$ .

Remarks

The capability index is

$c_{pk}=\min\left[\frac{\mathrm{USL}-\bar{x}}{3\sigma},\frac{\bar{x}-\mathrm{LSL}}{3\sigma}\right]$

where LSL and USL are the lower and upper specification limits, $\bar{x}$ is the center line, and

$\sigma=\frac{\bar{s}}{c_{4,n}\sqrt{n}}$