rRBS: Reparameterized Birnbaum-Saunders (RBS) distribution for...

Description Usage Arguments Details Value Note Author(s) Examples

View source: R/RBSdist.R

Description

The fuction RBS() defines the BS distribution, a two paramenter distribution, for a gamlss.family object to be used in GAMLSS fitting using using the function gamlss(), with mean equal to the parameter mu and sigma equal the precision parameter. The functions dRBS, pRBS, qRBS and rBS define the density, distribution function, quantile function and random genetation for the RBS parameterization of the RBS distribution.

Usage

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RBS(mu.link = "identity", sigma.link = "identity")
dRBS(x, mu = 1, sigma = 1, log = FALSE)
pRBS(q, mu = 1, sigma = 1, lower.tail = TRUE, log.p = FALSE)
qRBS(p, mu = 1, sigma = 1, lower.tail = TRUE, log.p = FALSE)
rRBS(n, mu = 1, sigma = 1)
plotRBS(mu = .5, sigma = 1, from = 0, to = 0.999, n = 101, ...)
meanRBS(obj)

Arguments

n

number of observations. If length(n) > 1, the length is taken to be the number required.

mu

vector of scale parameter values

sigma

vector of shape parameter values

mu.link

object for which the extraction of model residuals is meaningful.

sigma.link

type of residual to be used.

x, q

vector of quantiles

log,

log.p logical; if TRUE, probabilities p are given as log(p).

lower.tail

logical; if TRUE (default), probabilities are P[X <= x], otherwise, P[X > x]

p

vector of probabilities.

from

where to start plotting the distribution from

to

up to where to plot the distribution

obj

a fitted RBS object

...

other graphical parameters for plotting

Details

The parametrization of the normal distribution given in the function RBS() is

f_{Y}(y;μ,δ)=\frac{\exp≤ft(δ/2\right)√{δ+1}}{4√{πμ}\,y^{3/2}} ≤ft[y+\frac{δ μ}{δ+1}\right] \exp≤ft(-\frac{δ}{4} ≤ft[\frac{y\{δ+1\}}{δμ}+\frac{δμ}{y\{δ+1\}}\right]\right) y>0.

Value

returns a gamlss.family object which can be used to fit a normal distribution in the gamlss() function.

Note

For the function RBS(), mu is the mean and sigma is the precision parameter of the Birnbaum-Saunders distribution.

Author(s)

Manoel Santos-Neto [email protected], F.J.A. Cysneiros [email protected], Victor Leiva [email protected] and Michelli Barros [email protected]

Examples

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plotRBS()
dat <- rRBS(1000); hist(dat)
fit <- gamlss(dat~1,family=RBS(),method=CG())
meanRBS(fit)

santosneto/rbsmodels documentation built on May 26, 2017, 12:32 a.m.