| GammaDist {base} | R Documentation |
Density, distribution function, quantile function and random
generation for the Gamma distribution with parameters shape and
scale.
dgamma(x, shape, scale=1, log = FALSE) pgamma(q, shape, scale=1, lower.tail = TRUE, log.p = FALSE) qgamma(p, shape, scale=1, lower.tail = TRUE, log.p = FALSE) rgamma(n, shape, scale=1)
x, q |
vector of quantiles. |
p |
vector of probabilities. |
n |
number of observations. |
shape, scale |
shape and scale parameters. |
log, log.p |
logical; if TRUE, probabilities p are given as log(p). |
lower.tail |
logical; if TRUE (default), probabilities are P[X <= x], otherwise, P[X > x]. |
If scale is omitted, it assumes the default value of 1.
The Gamma distribution with parameters shape = a
and scale = b has density
f(x) = 1/(b^a Gamma(a)) x^(a-1) e^-(x/b)
for x > 0, a > 0 and b > 0.
dgamma gives the density,
pgamma gives the distribution function
qgamma gives the quantile function, and
rgamma generates random deviates.
gamma for the Gamma function, dbeta for
the Beta distribution and dchisq for the chi-square
distribution which is a special case of the Gamma distribution.
-log(dgamma(1:4, shape=1)) p <- (1:9)/10 pgamma(qgamma(p,shape=2), shape=2) 1 - 1/exp(qgamma(p, shape=1))