Geometric {base} | R Documentation |
These functions provide information about the geometric distribution
with parameter prob
. dgeom
gives the density, pgeom
gives the distribution function, qgeom
gives the quantile
function, and rgeom
generates random deviates.
dgeom(x, prob) pgeom(q, prob) qgeom(p, prob) rgeom(n, prob)
x,q |
vector of quantiles representing the number of failures in a sequence of Bernoulli trials before success occurs. |
p |
vector of probabilities. |
n |
number of observations to generate. |
prob |
probability of success in each trial. |
The geometric distribution with prob
= p has density
p(x) = p (1-p)^x
for x = 0, 1, 2, ...
If an element of x
is not integer, the result of pgeom
is zero, with a warning.
The quantile is left continuous: qgeom(q, prob)
is the largest
integer x such that P(X <= x) < q.
dnbinom
for the negative binomial which generalizes
the geometric distribution.
pp <- sort(c((1:9)/10, 1 - .2^(2:8))) print(qg <- qgeom(pp, prob = .2)) ## test that qgeom is an inverse of pgeom print(qg1 <- qgeom(pgeom(qg, prob=.2), prob =.2)) all(qg == qg1) Ni <- rgeom(20, prob = 1/4); table(factor(Ni, 0:max(Ni)))