Author: Freddy Hernandez
Date: 2026-02-21

# FWE distribution

#### Freddy Hernandez

#### 2026-02-21

    library(RelDists)
    #> Cargando paquete requerido: survival
    #> Cargando paquete requerido: EstimationTools
    #>
    #> ><<<<<<<<<<<<<<<<<<<<<<<<   EstimationTools Version 4.3.1   >>>>>>>>>>>>>>>>>>>>>>>><
    #>   Feel free to report bugs in https://github.com/Jaimemosg/EstimationTools/issues

# Flexible Weibull extension distribution

This distribution was proposed by Bebbington (2007). The probability density function \(f(x)\) and cumulative density function \(F(x)\) are given by:

\[f(x) = \left( \mu+ \frac{\sigma}{x^2} \right) e^{\mu x - \sigma / x} \exp \left( -e^{\mu x - \sigma / x} \right),\]

and

\[F(x) = 1 - \exp[-e^{\mu x - \sigma / x}], \quad x > 0.\]

respectively, where \(\mu > 0\), \(\sigma > 0\) and \(x > 0\).

Next figure shows possible shapes of the \(f(x)\) and \(F(x)\) for several values of the parameters.

Bebbington, M., C. D. Lai, and R. Zitikis. 2007. “A Flexible Weibull Extension.” Reliability Engineering & System Safety 92 (6): 719–26.