# Manuals/calci/WEIBULL

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**WEIBULL (Number,Alpha,Beta,Cumulative)**

- is the value of the function.
- and are the parameter of the distribution.
- is the logical value.
- WEIBULL(),returns the Weibull distribution.

## Description

- This function gives the value of the weibull distribution with 2-parameters.
- It is a continuous probability distribution.
- Weibull distribution also called Rosin Rammler distribution.
- It is used to model the lifetime of technical devices and is used to describe the particle size distribution of particles generated by grinding, milling and crushing operations.
- This distribution is closely related to the lognormal distribution.
- In , is the value to evaluate the function.
- is the shape parameter of the distribution. is the scale parameter of the distribution.
- is the logical value which determines the form of the distribution.
- When is TRUE, this function gives the value of the cumulative distribution. When is FALSE, then this function gives the value of the probability density function.
- When we are not omitting the value of , then it consider as FALSE.
- Weibull distribution is of two type :3-parameter weibull distribution and 2-parameter weibull distribution.
- This function gives the value of 2-parameter weibull distribution by setting the third parameter (location parameter) is zero.
- Also if alpha<1,then the failure rate of the device decreases over time.
- If alpha=1, then the failure rate of the device is constant over time.
- If alpha>1, then the failure rate of the device increases over time.
- The equation for cumulative distribution function is: =.
- The equation for probability density function is:

- When alpha =1, then this function gives the exponential with .
- This function gives the result as error when

1. Any one of the argument is non-numeric. 2. Number is negative. 3. Alpha or Beta

## Examples

- =WEIBULL(202,60,81,TRUE) = 1
- =WEIBULL(202,60,81,FALSE) = 0
- =WEIBULL(160,80,170,TRUE) = 0.00779805060
- =WEIBULL(160,80,170,FALSE) = 0.0038837823333
- = WEIBULL(10.5,2.1,5.3,TRUE) = 0.9850433821261
- =WEIBULL(10.5,2.1,5.3,FALSE) = 0.0125713406729

## Related Videos

## See Also

## References