GAMLSS families are the current available distributions that can be fitted using the `gamlss()`

function.

1 2 3 4 5 | ```
gamlss.family(object,...)
as.gamlss.family(object)
as.family(object)
## S3 method for class 'gamlss.family'
print(x,...)
``` |

`object` |
a gamlss family object e.g. |

`x` |
a gamlss family object e.g. |

`...` |
further arguments passed to or from other methods. |

There are several distributions available for the response variable in the `gamlss`

function.
The following table display their names and their abbreviations in `R`

. Note that the different distributions can be fitted
using their `R`

abbreviations
(and optionally excluding the brackets) i.e. family=BI(), family=BI are equivalent.

Distributions | R names | No of parameters |

Beta | `BE()` | 2 |

Beta Binomial | `BB()` | 2 |

Beta one inflated | `BEOI()` | 3 |

Beta zero inflated | `BEZI()` | 3 |

Beta inflated | `BEINF()` | 4 |

Binomial | `BI()` | 1 |

Box-Cox Cole and Green | `BCCG()` | 3 |

Box-Cox Power Exponential | `BCPE()` | 4 |

Box-Cox-t | `BCT()` | 4 |

Delaport | `DEL()` | 3 |

Exponential | `EXP()` | 1 |

Exponential Gaussian | `exGAUS()` | 3 |

Exponential generalized Beta type 2 | `EGB2()` | 4 |

Gamma | `GA()` | 2 |

Generalized Beta type 1 | `GB1()` | 4 |

Generalized Beta type 2 | `GB2()` | 4 |

Generalized Gamma | `GG()` | 3 |

Generalized Inverse Gaussian | `GIG()` | 3 |

Generalized t | `GT()` | 4 |

Geometric | `GEOM()` | 1 |

Gumbel | `GU()` | 2 |

Inverse Gamma | `IGAMMA()` | 2 |

Inverse Gaussian | `IG()` | 2 |

Johnson's SU | `JSU()` | 4 |

Logarithmic | `LG()` | 1 |

Logistic | `LO()` | 2 |

log-Normal | `LOGNO()` | 2 |

log-Normal (Box-Cox) | `LNO()` | 3 (1 fixed) |

Negative Binomial type I | `NBI()` | 2 |

Negative Binomial type II | `NBII()` | 2 |

Normal Exponential t | `NET()` | 4 (2 fixed) |

Normal | `NO()` | 2 |

Normal Family | `NOF()` | 3 (1 fixed) |

Pareto type 2 | `PARETO2()` | 2 |

Pareto type 2 original | `PARETO2o()` | 2 |

Power Exponential | `PE()` | 3 |

Power Exponential type 2 | `PE2()` | 3 |

Poison | `PO()` | 1 |

Poisson inverse Gaussian | `PIG()` | 2 |

Reverse generalized extreme | `RGE()` | 3 |

Reverse Gumbel | `RG()` | 2 |

Skew Power Exponential type 1 | `SEP1()` | 4 |

Skew Power Exponential type 2 | `SEP2()` | 4 |

Skew Power Exponential type 3 | `SEP3()` | 4 |

Skew Power Exponential type 4 | `SEP4()` | 4 |

Shash | `SHASH()` | 4 |

Shash original | `SHASHo()` | 4 |

Shash original 2 | `SHASH()` | 4 |

Sichel (original) | `SI()` | 3 |

Sichel (mu as the maen) | `SICHEL()` | 3 |

Skew t type 1 | `ST1()` | 3 |

Skew t type 2 | `ST2()` | 3 |

Skew t type 3 | `ST3()` | 3 |

Skew t type 4 | `ST4()` | 3 |

Skew t type 5 | `ST5()` | 3 |

t-distribution | `TF()` | 3 |

Waring | `WARING()` | 1 |

Weibull | `WEI()` | 2 |

Weibull(PH parameterization) | `WEI2()` | 2 |

Weibull (mu as mean) | `WEI3()` | 2 |

Yule | `YULE()` | 1 |

Zero adjusted binomial | `ZABI()` | 2 |

Zero inflated binomial | `ZIBI()` | 2 |

Zero adjusted logarithmic | `ZALG()` | 2 |

Zero inflated poisson | `ZIP()` | 2 |

Zero inf. poiss.(mu as mean) | `ZIP2()` | 2 |

Zero adjusted poisson | `ZAP()` | 2 |

Zero adjusted IG | `ZAIG()` | 2 |

Note that some of the distributions are in the package `gamlss.dist`

.
The parameters of the distributions are in order, ** mu** for location,

`sigma`

`nu`

`tau`

`BCCG`

family `mu`

is the median, `sigma`

approximately the coefficient of variation, and `nu`

the skewness parameter.
The parameters for `BCPE`

distribution have the same interpretation with the extra fourth parameter `tau`

modelling
the kurtosis of the distribution. The parameters for BCT have the same interpretation except that
All of the distribution in the above list are also provided with the corresponding `d`

, `p`

, `q`

and `r`

functions
for density (pdf), distribution function (cdf), quantile function and random generation function respectively, (see individual distribution for details).

The above GAMLSS families return an object which is of type `gamlss.family`

. This object is used to define the family in the `gamlss()`

fit.

More distributions will be documented in later GAMLSS releases. Further user defined distributions can be incorporate relatively easy, see, for example, the help documentation accompanying the gamlss library.

Mikis Stasinopoulos mikis.stasinopoulos@gamlss.org, Bob Rigby and Calliope Akantziliotou

Rigby, R. A. and Stasinopoulos D. M. (2005). Generalized additive models for location, scale and shape,(with discussion),
*Appl. Statist.*, **54**, part 3, pp 507-554.

Stasinopoulos D. M., Rigby R.A. and Akantziliotou C. (2006) Instructions on how to use the GAMLSS package in R. Accompanying documentation in the current GAMLSS help files, (see also http://www.gamlss.org/).

Stasinopoulos D. M. Rigby R.A. (2007) Generalized additive models for location scale and shape (GAMLSS) in R.
*Journal of Statistical Software*, Vol. **23**, Issue 7, Dec 2007, http://www.jstatsoft.org/v23/i07.

`BE`

,`BB`

,`BEINF`

,`BI`

,`LNO`

,`BCT`

,
`BCPE`

,`BCCG`

,
`GA`

,`GU`

,`JSU`

,`IG`

,`LO`

,
`NBI`

,`NBII`

,`NO`

,`PE`

,`PO`

,
`RG`

,`PIG`

,`TF`

,`WEI`

,`WEI2`

,
`ZIP`

1 2 | ```
normal<-NO(mu.link="log", sigma.link="log")
normal
``` |

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