WorksheetFunction.Weibull Method

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Excel Developer Reference

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

Syntax

expression.Weibull(Arg1, Arg2, Arg3, Arg4)

expression   A variable that represents a WorksheetFunction object.

Parameters

Name Required/Optional Data Type Description
Arg1 Required Double X - the value at which to evaluate the function.
Arg2 Required Double Alpha - a parameter to the distribution.
Arg3 Required Double Beta - a parameter to the distribution.
Arg4 Required Boolean Cumulative - determines the form of the function.

Return Value
Double

Remarks

  • 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:

    Equation

  • The equation for the Weibull probability density function is:

    Equation

  • When alpha = 1, WEIBULL returns the exponential distribution with:

    Equation

See Also