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. `n` The number of draws to make from the distribution. `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.

### Details

The Noncentral Hypergeometric is particularly useful for conditional inference for (2 x 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 0.5-2 Index]