felix {VGAM} | R Documentation |
Estimates the parameter of a Felix distribution by maximum likelihood estimation.
felix(link = "elogit", earg = if (link == "elogit") list(min = 0, max = 0.5) else list(), method.init=1)
link, earg |
Link function and extra argument for the parameter.
See Links for more choices and for general information.
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method.init |
See CommonVGAMffArguments .
Valid values are 1, 2, 3 or 4.
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The Felix distribution is an important basic Lagrangian distribution. The density function is
f(y;a) = (1 / ((y-1)/2)!) * y^((y-3)/2) * a^((y-1)/2) * exp(-ay)
where y=1,3,5,... and 0 < a < 0.5. The mean is 1/(1-2a) (returned as the fitted values). Fisher scoring is implemented.
An object of class "vglmff"
(see vglmff-class
).
The object is used by modelling functions such as vglm
and vgam
.
T. W. Yee
Consul, P. C. and Famoye, F. (2006) Lagrangian Probability Distributions, Boston: Birkhauser.
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)