R: The Noncentral Hypergeometric Distribution

NoncenHypergeom {MCMCpack} | R Documentation

## The Noncentral Hypergeometric Distribution

### Description

Evaluates the density at a single point or all points, and generate random draws from the Noncentral Hypergeometric distribution.

### Usage

    dnoncenhypergeom(x = NA, n1, n2, m1, psi)

    rnoncenhypergeom(n, n1, n2, m1, psi)

### Arguments

`x` | The location to evaluate the density. If `x` is NA, then a matrix is returned with the density evaluated at all possible points.
`n1` | The size of group one.
`n2` | The size of group two.
`m1` | The observed number of positive outcomes (in both groups).
`psi` | Odds ratio.
`n` | The number of draws to make from the distribution.

### Details

The Noncentral Hypergeometric is particularly useful for conditional inference for (2 \times 2) tables. We use the parameterization and algorithms of Liao and Rosen (2001). The underlying R code is based on their published code. See their article for details of the parameterization.

### Value

`dnoncenhypergeom` evaluates the density at point `x`, or a matrix with the first column containing the possible values of the random variable, and the second column containing the probabilities.

`rnoncenhypergeom` returns a list of `n` random draws from the distribution.

### Source

J. G. Liao and Ori Rosen. 2001. “Fast and Stable Algorithms for Computing and Sampling From the Noncentral Hypergeometric Distribution." The American Statistician. 55: 366-369.

### Examples

      density <- dnoncenhypergeom(NA, 500, 500, 500, 6.0)
      draws <- rnoncenhypergeom(10, 500, 500, 500, 6.0)

[Package MCMCpack version 1.4-0 Index]