WorksheetFunction.Weibull Method

  • Article

Returns the Weibull distribution. Use this distribution in reliability analysis, such as calculating a device's mean time to failure.

Namespace:  Microsoft.Office.Interop.Excel
Assembly:  Microsoft.Office.Interop.Excel (in Microsoft.Office.Interop.Excel.dll)

Syntax

'Declaration
Function Weibull ( _
    Arg1 As Double, _
    Arg2 As Double, _
    Arg3 As Double, _
    Arg4 As Boolean _
) As Double
'Usage
Dim instance As WorksheetFunction
Dim Arg1 As Double
Dim Arg2 As Double
Dim Arg3 As Double
Dim Arg4 As Boolean
Dim returnValue As Double

returnValue = instance.Weibull(Arg1, Arg2, _
    Arg3, Arg4)

double Weibull(
    double Arg1,
    double Arg2,
    double Arg3,
    bool Arg4
)

Parameters

  • Arg1
    Type: System.Double

    X - the value at which to evaluate the function.

  • Arg2
    Type: System.Double

    Alpha - a parameter to the distribution.

  • Arg3
    Type: System.Double

    Beta - a parameter to the distribution.

  • Arg4
    Type: System.Boolean

    Cumulative - determines the form of the function.

Return Value

Type: System.Double

Remarks

Important

This function has been replaced with one or more new functions that may provide improved accuracy and whose names better reflect their usage. This function is still available for compatibility with earlier versions of Excel. However, if backward compatibility is not required, you should consider using the new functions from now on, because they more accurately describe their functionality. For more information about the new function, see the Weibull_Dist(Double, Double, Double, Boolean) method.

If x, alpha, or beta is nonnumeric, Weibull returns the #VALUE! error value. If x < 0, Weibull returns the #NUM! error value.

If alpha ≤ 0 or if beta ≤ 0, Weibull returns the #NUM! error value.

The equation for the Weibull cumulative distribution function is:

Figure 1: Equation for the Weibull cumulative distribution

Equation for the Weibull cumulative distribution

The equation for the Weibull probability density function is:

Figure 2: Equation for the Weibull probability density

Equation for the Weibull probability density

When alpha = 1, Weibull returns the exponential distribution with:

Figure 3: Equation

Equation

See Also

Reference

WorksheetFunction Interface

WorksheetFunction Members

Microsoft.Office.Interop.Excel Namespace