| Exponential {stats} | R Documentation |
Density, distribution function, quantile function and random
generation for the exponential distribution with rate rate
(i.e., mean 1/rate).
dexp(x, rate = 1, log = FALSE) pexp(q, rate = 1, lower.tail = TRUE, log.p = FALSE) qexp(p, rate = 1, lower.tail = TRUE, log.p = FALSE) rexp(n, rate = 1)
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. |
rate |
vector of rates. |
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 rate is not specified, it assumes the default value of
1.
The exponential distribution with rate λ has density
f(x) = lambda e^(- lambda x)
for x >= 0.
dexp gives the density,
pexp gives the distribution function,
qexp gives the quantile function, and
rexp generates random deviates.
The cumulative hazard H(t) = - log(1 - F(t))
is -pexp(t, r, lower = FALSE, log = TRUE).
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
exp for the exponential function,
dgamma for the gamma distribution and
dweibull for the Weibull distribution, both of which
generalize the exponential.
dexp(1) - exp(-1) #-> 0