duigd gives the density, puigd gives the distribution
function, quigd gives the quantile function and ruigd generates
random deviates.
Arguments
x, q
vector of quantiles.
mu
a mean parameter.
lambda
a scale parameter.
log, log.p
logical; if TRUE, probabilities p are given as log(p).
lower.tail
logical; if TRUE (default), probabilities are
\(P\left[ X\leq x\right]\), otherwise, \(P\left[ X>x\right] \).
p
vector of probabilities.
n
number of observations. If length(n) > 1, the length is taken
to be the number required.
Details
The Unit Inverse Gaussian distribution scale
parameter \(\lambda\) and mean
parameter \(\mu\), has density
$$f\left( x\right) =\sqrt{\frac{\lambda }{2\pi }}
\frac{1}{x^{3/2}}e^{-\frac{ \lambda }{2\mu ^{2}x}\left( x-\mu \right) ^{2}},$$
where
$$x>0,~\mu ,\lambda >0.$$
References
Ghitany, M., Mazucheli, J., Menezes, A. ve Alqallaf, F., 2019,
The unit-inverse Gaussian distribution: A new alternative to two-parameterdistributions on the unit interval, Communications in Statistics-Theory andMethods, 48 (14), 3423-3438.