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mvtnorm (version 1.0-5)

qmvnorm: Quantiles of the Multivariate Normal Distribution

Description

Computes the equicoordinate quantile function of the multivariate normal distribution for arbitrary correlation matrices based on inversion of pmvnorm.

Usage

qmvnorm(p, interval = NULL, tail = c("lower.tail", "upper.tail", "both.tails"), mean = 0, corr = NULL, sigma = NULL, algorithm = GenzBretz(), ptol = 0.001, maxiter = 500, trace = FALSE, ...)

Arguments

p
probability.
interval
optional, a vector containing the end-points of the interval to be searched. Does not need to contain the true quantile, just used as starting values by the root-finder. If equal to NULL a guess is used.
tail
specifies which quantiles should be computed. lower.tail gives the quantile $x$ for which $P[X \le x] = p$, upper.tail gives $x$ with $P[X > x] = p$ and both.tails leads to $x$ with $P[-x \le X \le x] = p$.
mean
the mean vector of length n.
corr
the correlation matrix of dimension n.
sigma
the covariance matrix of dimension n. Either corr or sigma can be specified. If sigma is given, the problem is standardized. If neither corr nor sigma is given, the identity matrix is used for sigma.
algorithm
an object of class GenzBretz, Miwa or TVPACK specifying both the algorithm to be used as well as the associated hyper parameters.
ptol, maxiter, trace
Parameters passed to the stochastic root-finding algorithm. Iteration stops when the 95% confidence interval for the predicted quantile is inside [p-ptol, p+ptol]. maxiter is the maximum number of iterations for the root finding algorithm. trace prints the iterations of the root finder.
...
additional parameters to be passed to GenzBretz.

Value

A list with two components: quantile and f.quantile give the location of the quantile and the difference between the distribution function evaluated at the quantile and p.

Details

Only equicoordinate quantiles are computed, i.e., the quantiles in each dimension coincide. The result is seed dependend.

See Also

pmvnorm, qmvt

Examples

Run this code
qmvnorm(0.95, sigma = diag(2), tail = "both")

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