Density, distribution, quantile function and random number generation for the normal inverse gaussian distribution generalized parameterized in terms of mean, standard deviation, skew and shape parameters.
log: (logical) if TRUE, probabilities p are given as log(p).
lower_tail: if TRUE (default), probabilities are P[X≤x] otherwise, P[X>x].
p: vector of probabilities.
n: number of observations.
Returns
d gives the density, p gives the distribution function, q gives the quantile function and r generates random deviates. Output depends on x or q length, or n for the random number generator.