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Weibull Plot
Weibull Distribution

A statistical approach, using graphical plots of the time-to-failure. A family of distributions that evaluates a design and is used to deduce the percentage of failures of a design’s population for a given time all the way through a design's life expectancies.

The distributions typically use the formula of…

Weibull Formula

You can make predictions using a Weibull Probability Distribution, but it can be cumbersome, and the predictions are usually plotted on Weibull probability paper, but to make a valid Weibull plot, at least seven points are needed. Any fewer can cast doubt on the ability of a plot to see any underlying pattern of variation.

A plot could look like the following.

The example below is from the Dale H. Besterfield, Ph.D. book, Quality Control Sixth Edition, that includes a CD of Excel macros.

Weibull Plot Example

For another example, see the National Institute of Standards and Technology's pages titled Weibull Distribution and Weibull Plot

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Last Updated: Wednesday, 17-May-06 10:21:08 PDT