PermutationDistribution-methods {coin} R Documentation

## Computation of the Permutation Distribution

### Description

Methods for computation of the density function, distribution function, quantile function, random numbers and support of the permutation distribution.

### Usage

```## S4 method for signature 'NullDistribution'
dperm(object, x, ...)
## S4 method for signature 'IndependenceTest'
dperm(object, x, ...)

## S4 method for signature 'NullDistribution'
pperm(object, q, ...)
## S4 method for signature 'IndependenceTest'
pperm(object, q, ...)

## S4 method for signature 'NullDistribution'
qperm(object, p, ...)
## S4 method for signature 'IndependenceTest'
qperm(object, p, ...)

## S4 method for signature 'NullDistribution'
rperm(object, n, ...)
## S4 method for signature 'IndependenceTest'
rperm(object, n, ...)

## S4 method for signature 'NullDistribution'
support(object, ...)
## S4 method for signature 'IndependenceTest'
support(object, ...)
```

### Arguments

 `object` an object from which the density function, distribution function, quantile function, random numbers or support of the permutation distribution can be computed. `x, q` a numeric vector, the quantiles for which the density function or distribution function is computed. `p` a numeric vector, the probabilities for which the quantile function is computed. `n` a numeric vector, the number of observations. If `length(n) > 1`, the length is taken to be the number required. `...` further arguments to be passed to methods.

### Details

The methods `dperm`, `pperm`, `qperm`, `rperm` and `support` compute the density function, distribution function, quantile function, random deviates and support, respectively, of the permutation distribution.

### Value

The density function, distribution function, quantile function, random deviates or support of the permutation distribution computed from `object`. A numeric vector.

### Note

The density of asymptotic permutation distributions for maximum-type tests or exact permutation distributions obtained by the split-up algoritm is reported as `NA`. The quantile function of asymptotic permutation distributions for maximum-type tests cannot be computed for `p` less than 0.5, due to limitations in the mvtnorm package. The support of exact permutation distributions obtained by the split-up algorithm is reported as `NA`.

In versions of coin prior to 1.1-0, the support of asymptotic permutation distributions was given as an interval containing 99.999 % of the probability mass. It is now reported as `NA`.

### Examples

```## Two-sample problem
dta <- data.frame(
y = rnorm(20),
x = gl(2, 10)
)

at <- ansari_test(y ~ x, data = dta, distribution = "exact")

## Support of the exact distribution of the Ansari-Bradley statistic
supp <- support(at)

## Density of the exact distribution of the Ansari-Bradley statistic
dens <- dperm(at, x = supp)

## Plotting the density
plot(supp, dens, type = "s")

## 95% quantile
qperm(at, p = 0.95)

## One-sided p-value
pperm(at, q = statistic(at))

## Random number generation
rperm(at, n = 5)
```

[Package coin version 1.4-1 Index]