Poisson {base}

R Documentation

The Poisson Distribution

Description

These functions provide information about the Poisson distribution with parameter lambda. dpois gives the density, ppois gives the distribution function qpois gives the quantile function and rpois generates random deviates.

The Poisson distribution has density

p(x) = \frac{{\lambda}^{x} {e}^{-\lambda}}{x!}

for x = 0, 1, 2, \ldots.

Usage

dpois(x, lambda)
ppois(q, lambda)
qpois(p, lambda)
rpois(n, lambda)

Arguments

x	vector of (positive) quantiles.
p	vector of probabilities.
n	number of random values to return.
lambda	vector of positive means.

Examples

-log(dpois(0:7, lambda=1) * gamma(1+ 0:7))
Ni <- rpois(50, lam= 4); table(factor(Ni, 0:max(Ni)))

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