# Chi: The Chi Distribution In adehabitatLT: Analysis of Animal Movements

 Chi R Documentation

## The Chi Distribution

### Description

Density, distribution function, quantile function and random generation for the chi distribution with df degrees of freedom.

### Usage

dchi(x, df = 2)
pchi(q, df = 2, lower.tail = TRUE, ...)
qchi(p, df = 2, lower.tail = TRUE)
rchi(n, df = 2)


### Arguments

 x,q vector of quantiles. p vector of probabilities. n number of observations. If length(n) > 1, the length is taken to be the number required. df degrees of freedom (non-negative, but can be non-integer). lower.tail logical; if TRUE (default), probabilities are P[X <= x], otherwise, P[X > x]. ... additional arguments to be passed to the function integrate.

### Details

The chi distribution with df = n > 0 degrees of freedom has density

f_n (x) = 2^{1-n/2} x^{n-1} e^{\frac{-(x^2)}{2}} / \Gamma (n/2)

for x > 0. This distribution is used to describe the square root of a variable distributed according to a chi-square distribution.

### Value

dchi gives the density, pchi gives the distribution function, qchi gives the quantile function, and rchi generates random deviates.

### Author(s)

Clement Calenge clement.calenge@ofb.gouv.fr

### References

Evans, M., Hastings, N. and Peacock, B. (2000) Statistical Distributions, 3rd ed. Wiley, New York.

Chisquare

### Examples


opar <- par(mfrow = c(2,2))

hist(rchi(100), ncla = 20, main="The Chi distribution")

plot(tutu <- seq(0, 5, length=20), dchi(tutu, df = 2), xlab = "x",
ylab = "probability density", type = "l")

plot(tutu, pchi(tutu), xlab = "x", ylab = "Repartition function",
type = "l")

par(opar)



adehabitatLT documentation built on April 6, 2023, 5:18 p.m.