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WEIBULL

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

Syntax: WEIBULL(Number, Beta, Eta, Cumulative)

• Number is the value at which to evaluate the function.

• Beta is a parameter to the distribution.

• Eta is a parameter to the distribution.

• Cumulative determines the form of the function.

Remarks:

• Number, Beta and Eta must be numerical.

• Number must be greater than or equal to 0.

• Beta and Eta must be greater than 0.

• The equation for the Weibull cumulative distribution function is:

• The equation for the Weibull probability density function is:

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

Example:

• WEIBULL(105, 20, 100, TRUE) = 0.929581

• WEIBULL(105, 20, 100, FALSE) = 0.035589