dhpois | R Documentation |
Density, distribution function, quantile function, and random
generation for the zero-hurdle Poisson distribution with
parameters lambda
and pi
.
dhpois(x, lambda, pi, log = FALSE) phpois(q, lambda, pi, lower.tail = TRUE, log.p = FALSE) qhpois(p, lambda, pi, lower.tail = TRUE, log.p = FALSE) rhpois(n, lambda, pi)
x |
vector of (non-negative integer) quantiles. |
lambda |
vector of (non-negative) Poisson parameters. |
pi |
vector of zero-hurdle probabilities in the unit interval. |
log, log.p |
logical indicating whether probabilities p are given as log(p). |
q |
vector of quantiles. |
lower.tail |
logical indicating whether probabilities are P[X ≤ x] (lower tail) or P[X > x] (upper tail). |
p |
vector of probabilities. |
n |
number of random values to return. |
All functions follow the usual conventions of d/p/q/r functions
in base R. In particular, all four hpois
functions for the
hurdle Poisson distribution call the corresponding pois
functions for the Poisson distribution from base R internally.
Note, however, that the precision of qhpois
for very large
probabilities (close to 1) is limited because the probabilities
are internally handled in levels and not in logs (even if log.p = TRUE
).
HurdlePoisson
, dpois
## theoretical probabilities for a hurdle Poisson distribution x <- 0:8 p <- dhpois(x, lambda = 2.5, pi = 0.75) plot(x, p, type = "h", lwd = 2) ## corresponding empirical frequencies from a simulated sample set.seed(0) y <- rhpois(500, lambda = 2.5, pi = 0.75) hist(y, breaks = -1:max(y) + 0.5)
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