The Weibull distribution is continuous. It describes data resulting from fatigue tests and can be used to describe failure time in reliability studies or the breaking strengths of materials in reliability and quality control tests. Weibull distributions are also used to represent various physical quantities, such as wind speed.
This flexible distribution can assume the properties of other distributions. When the shape parameter is equal to 1.0, the Weibull distribution is identical to the exponential distribution. The location parameter lets you set up an exponential distribution to start at a location other than 0.0. When the shape parameter is less than 1.0, the Weibull distribution becomes a steeply declining curve. A manufacturer may find this effect useful in describing part failures during a burn-in period.
When shape parameters equal 1, it is identical to Exponential; when equal to 2, it is identical to Rayleigh.