GammaDist {base} | R Documentation |
dgamma(x, shape, scale=1) pgamma(q, shape, scale=1) qgamma(p, shape, scale=1) rgamma(n, shape, scale=1)
x,q |
vector of quantiles. |
p |
vector of probabilities. |
n |
number of observations. |
shape, scale |
shape and scale parameters. |
These functions provide information about the gamma
distribution with parameters shape
and scale
.
dgamma
gives the density,
pgamma
gives the distribution function
qgamma
gives the quantile function
and
rgamma
generates random deviates.
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.
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))