Six Sigma SPC OEM Products
Six Sigma and SPC (Statistical Process Control) Software Applications

Six Sigma SPC - 2070 W. Washington St. #5 Springfield IL 62702  Ph: 217.698.0063
6 Sigma Statistical Process Control (SPC) Software for Windows 95/98/NT/2000/XP/ME

Home Search Capability Studies Links
Products Services
Prices FAQ
About Support
Contact Quality Control Dictionary and Glossary Free Desktop 6 Sigma Calculator Forum
Quality Books Six Sigma and SPC Articles Free Online 6 Sigma Calculator Free Newsletter

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

Back to the Quality Control Dictionary and Glossary

Click Here!


Copyright ? 2005 Six Sigma SPC / Jim Winings All Rights Reserved
Privacy Statement - Disclaimer - Copyright - Site Map

Last Updated: Saturday, 10-Jun-06 15:50:57 PDT