WorksheetFunction.Weibull(Double, Double, Double, Boolean) Method
Definition
Important
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Returns the Weibull distribution. Use this distribution in reliability analysis, such as calculating a device's mean time to failure.
public:
double Weibull(double Arg1, double Arg2, double Arg3, bool Arg4);public double Weibull (double Arg1, double Arg2, double Arg3, bool Arg4);Public Function Weibull (Arg1 As Double, Arg2 As Double, Arg3 As Double, Arg4 As Boolean) As DoubleParameters
- Arg1
- Double
X - the value at which to evaluate the function.
- Arg2
- Double
Alpha - a parameter to the distribution.
- Arg3
- Double
Beta - a parameter to the distribution.
- Arg4
- Boolean
Cumulative - determines the form of the function.
Returns
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
The equation for the Weibull probability density function is:
Figure 2: Equation for the Weibull probability density
When alpha = 1, Weibull returns the exponential distribution with:
Figure 3: Equation