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Pareto: The Pareto Distribution

Description

Density, distribution function, quantile function, random generation, raw moments and limited moments for the Pareto distribution with parameters shape and scale.

Usage

dpareto(x, shape, scale, log = FALSE)
  ppareto(q, shape, scale, lower.tail = TRUE, log.p = FALSE)
  qpareto(p, shape, scale, lower.tail = TRUE, log.p = FALSE)
  rpareto(n, shape, scale)
  mpareto(order, shape, scale)
  levpareto(limit, shape, scale, order = 1)

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.
shape, scale
parameters. Must be strictly positive.
log, log.p
logical; if TRUE, probabilities/densities $p$ are returned as $\log(p)$.
lower.tail
logical; if TRUE (default), probabilities are $P[X \le x]$, otherwise, $P[X > x]$.
order
order of the moment.
limit
limit of the loss variable.

Value

  • dpareto gives the density, ppareto gives the distribution function, qpareto gives the quantile function, rpareto generates random deviates, mpareto gives the $k$th raw moment, and levpareto gives the $k$th moment of the limited loss variable.

    Invalid arguments will result in return value NaN, with a warning.

Details

The Pareto distribution with parameters shape $= \alpha$ and scale $= \theta$ has density: $$f(x) = \frac{\alpha \theta^\alpha}{(x + \theta)^{\alpha + 1}}$$ for $x > 0$, $\alpha > 0$ and $\theta$.

The $k$th raw moment of the random variable $X$ is $E[X^k]$ and the $k$ limited moment at some limit $d$ is $E[\min(X, d)]$.

References

Klugman, S. A., Panjer, H. H. and Willmot, G. E. (2004), Loss Models, From Data to Decisions, Second Edition, Wiley.

Examples

Run this code
exp(dpareto(2, 3, 4, log = TRUE))
p <- (1:10)/10
ppareto(qpareto(p, 2, 3), 2, 3)
mpareto(1, 2, 3)
levpareto(10, 2, 3, order = 1)

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