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The Chi-Square Distribution

Usage

dchisq(x, df)
pchisq(q, df)
qchisq(p, df)
rchisq(n, df)

Value

These functions provide information about the chi-square distribution with df degrees of freedom. dchisq gives the density, pchisq gives the distribution function qchisq gives the quantile function and rchisq generates random deviates.

The chi-square distribution with df = n degrees of freedom has density

f(x) = 1 / (2^(n/2) Gamma(n/2)) x^(n/2-1) e^(-x/2)

for x > 0.

See Also

dnchisq, dgamma, dexp.

Examples

dchisq(1, df=1:3)
x <- 1:10
## Chisquare( df = 2) is a special exponential distribution
dchisq(x, df=2) == dexp(x, 1/2)
pchisq(x, df=2) == pexp(x, 1/2)#- only approximately