WorksheetFunction.Weibull method (Excel)

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

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 method.

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  

The equation for the Weibull probability density function is  

When alpha = 1, Weibull returns the exponential distribution with  

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