VGAM (version 0.7-5)

felix: Felix Distribution Family Function

Description

Estimates the parameter of a Felix distribution by maximum likelihood estimation.

Usage

felix(link = "elogit", earg = if (link == "elogit") list(min
      = 0, max = 0.5) else list(), method.init=1)

Arguments

link, earg

Link function and extra argument for the parameter. See Links for more choices and for general information.

method.init

See CommonVGAMffArguments. Valid values are 1, 2, 3 or 4.

Value

• An object of class "vglmff" (see vglmff-class). The object is used by modelling functions such as vglm and vgam.

Details

The Felix distribution is an important basic Lagrangian distribution. The density function is $$f(y;a)=\frac{1}{((y-1)/2)!}{y}^{(y-3)/2}{a}^{(y-1)/2}\exp (-ay)$$ where $y=1,3,5,\ldots$ and $0 < a < 0.5$. The mean is $1/(1-2a)$ (returned as the fitted values). Fisher scoring is implemented.

References

Consul, P. C. and Famoye, F. (2006) Lagrangian Probability Distributions, Boston: Birkhauser.

See Also

dfelix, borel.tanner.

Examples

y = 2*rpois(n <- 200, 1) + 1   # Not real data!
fit = vglm(y ~ 1, felix, trace=TRUE, crit="c")
coef(fit, matrix=TRUE)
Coef(fit)
summary(fit)