distribution

Weibull distribution models

The Weibull distribution is widely used in reliability and life (failure rate) data analysis. This module provides the one-, two-, and three-parameter Weibull distributions.

The three-parameter Weibull distribution is

\[y=ab(x-c)^{b-1}\exp{[-a(x-c)^b]}\]

where \(a\) is the scale parameter, \(b\) is the shape parameter, and \(c\) is the location parameter.

The two-parameter Weibull distribution

\[y=abx^{b-1}\exp{(-ax^b)}\]

has \(x-c\) replaced with \(x\).

The one-parameter Weibull distribution has the shape parameter fixed, so only the scale parameter is fitted.

Functions

weibull

General three-parameter Weibull distribution.