WEIBULL

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

Syntax

WEIBULL(x,alpha,beta,cumulative)

X is the value at which to evaluate the function.

Alpha is a parameter to the distribution.

Beta is a parameter to the distribution.

Cumulative determines the form of the function.

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:

  

Example

The example may be easier to understand if you copy it to a blank worksheet.

How to copy an example

1. Create a blank workbook or worksheet.
2. Select the example in the Help topic.

   Note Do not select the row or column headers.

   Selecting an example from Help

3. Press CTRL+C.
4. In the worksheet, select cell A1, and press CTRL+V.
5. To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.

See also:

• EXPONDIST
• Statistical functions