Description Usage Arguments Value Author(s) References Examples
See Czado et al. (2009).
1 2 3 |
x |
numeric vector representing the observed counts. |
pdistr |
either a list of predictive cumulative distribution functions for
the observations |
J |
the number of bins of the histogram. |
relative |
logical indicating if relative frequency or the density should be plotted. |
... |
ignored if |
plot |
a list of arguments for |
an object of class "pit"
, which inherits from class
"histogram"
(see hist
).
It is returned invisibly if a plot is produced.
Michaela Paul and Sebastian Meyer
Czado, C., Gneiting, T. & Held, L. (2009): Predictive model assessment for count data. Biometrics, 65, 1254-1261.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | ## Simulation example of Czado et al. (2009, Section 2.4)
set.seed(100)
x <- rnbinom(200, mu = 5, size = 2)
pdistrs <- list("NB(5,0)" = function (x) ppois(x, lambda=5),
"NB(5,1/2)" = function (x) pnbinom(x, mu=5, size=2),
"NB(5,1)" = function (x) pnbinom(x, mu=5, size=1))
## Reproduce Figure 1
op <- par(mfrow = c(1,3))
for (i in seq_along(pdistrs)) {
pit(x, pdistr = pdistrs[[i]], J = 10, relative = TRUE,
plot = list(ylim = c(0,2.75), main = names(pdistrs)[i]))
box()
}
par(op)
## Alternative call using ... arguments for pdistr (less efficient)
stopifnot(identical(pit(x, "pnbinom", mu = 5, size = 2, plot = FALSE),
pit(x, pdistrs[[2]], plot = FALSE)))
|
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