| 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)))