IW | R Documentation |
The Inverse Weibull distribution
IW(mu.link = "log", sigma.link = "log")
mu.link |
defines the mu.link, with "log" link as the default for the mu parameter. |
sigma.link |
defines the sigma.link, with "log" link as the default for the sigma. |
The Inverse Weibull distribution with parameters mu
,
sigma
has density given by
f(x) = μ σ x^{-σ-1} \exp(μ x^{-σ})
for x > 0, μ > 0 and σ > 0
Returns a gamlss.family object which can be used to fit a IW distribution in the gamlss()
function.
Johan David Marin Benjumea, johand.marin@udea.edu.co
almalki2014modificationsRelDists
\insertRefdrapella1993complementaryRelDists
dIW
# Example 1 # Generating some random values with # known mu and sigma y <- rIW(n=100, mu=5, sigma=2.5) # Fitting the model require(gamlss) mod <- gamlss(y~1, mu.fo=~1, sigma.fo=~1, family='IW', control=gamlss.control(n.cyc=5000, trace=FALSE)) # Extracting the fitted values for mu, sigma and nu # using the inverse link function exp(coef(mod, what='mu')) exp(coef(mod, what='sigma')) # Example 2 # Generating random values under some model n <- 200 x1 <- rpois(n, lambda=2) x2 <- runif(n) mu <- exp(2 + -1 * x1) sigma <- exp(2 - 2 * x2) x <- rIW(n=n, mu, sigma) mod <- gamlss(x~x1, mu.fo=~1, sigma.fo=~x2, family=IW, control=gamlss.control(n.cyc=5000, trace=FALSE)) coef(mod, what="mu") coef(mod, what="sigma")
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