CIcdfplot: Empirical cumulative distribution function with pointwise...

Description Usage Arguments Details Author(s) References See Also Examples

View source: R/CIcdfplot.R

Description

cdfband plots the empirical cumulative distribution function with the bootstraped pointwise confidence intervals on probabilities of on quantiles.

Usage

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CIcdfplot(b, CI.output, CI.type = "two.sided", CI.level = 0.95, CI.col = "red", 
  CI.lty = 2, CI.fill = NULL, CI.only = FALSE, xlim, ylim, xlogscale = FALSE, 
  ylogscale = FALSE, main, xlab, ylab, datapch, datacol, fitlty, fitcol, fitlwd, 
  horizontals = TRUE, verticals = FALSE, do.points = TRUE, use.ppoints = TRUE, 
  a.ppoints = 0.5, lines01 = FALSE, ...)

Arguments

b

One "bootdist" object.

CI.output

The quantity on which (bootstraped) bootstraped confidence intervals are computed: either "probability" or "quantile").

CI.type

Type of confidence intervals : either "two.sided" or one-sided intervals ("less" or "greater").

CI.level

The confidence level.

CI.col

the color of the confidence intervals.

CI.lty

the line type of the confidence intervals.

CI.fill

a color to fill the confidence area. Default is NULL corresponding to no filling.

CI.only

A logical whether to plot empirical and fitted distribution functions or only the confidence intervals. Default to FALSE.

xlim

The x-limits of the plot.

ylim

The y-limits of the plot.

xlogscale

If TRUE, uses a logarithmic scale for the x-axis.

ylogscale

If TRUE, uses a logarithmic scale for the y-axis.

main

A main title for the plot, see also title.

xlab

A label for the x-axis, defaults to a description of x.

ylab

A label for the y-axis, defaults to a description of y.

datapch

An integer specifying a symbol to be used in plotting data points, see also points (only for non censored data).

datacol

A specification of the color to be used in plotting data points.

fitcol

A (vector of) color(s) to plot fitted distributions. If there are fewer colors than fits they are recycled in the standard fashion.

fitlty

A (vector of) line type(s) to plot fitted distributions/densities. If there are fewer values than fits they are recycled in the standard fashion. See also par.

fitlwd

A (vector of) line size(s) to plot fitted distributions/densities. If there are fewer values than fits they are recycled in the standard fashion. See also par.

horizontals

If TRUE, draws horizontal lines for the step empirical cdf function (only for non censored data). See also plot.stepfun.

do.points

logical; if TRUE, also draw points at the x-locations. Default is true (only for non censored data).

verticals

If TRUE, draws also vertical lines for the empirical cdf function. Only taken into account if horizontals=TRUE (only for non censored data).

use.ppoints

If TRUE, probability points of the empirical distribution are defined using function ppoints as (1:n - a.ppoints)/(n - 2a.ppoints + 1) (only for non censored data). If FALSE, probability points are simply defined as 1:n / n. This argument is ignored for discrete data.

a.ppoints

If use.ppoints=TRUE, this is passed to function ppoints (only for non censored data).

lines01

A logical to plot two horizontal lines at h=0 and h=1 for cdfcomp.

...

Further graphical arguments passed to matlines or polygon, respectively when CI.fill=FALSE and CI.fill=TRUE.

Details

CIcdfplot provides a plot of the empirical distribution using cdfcomp or cdfcompcens, with bootstraped pointwise confidence intervals on probabilities (y values) or on quantiles (x values). Each interval is computed by evaluating the quantity of interest (probability associated to an x value or quantile associated to an y value) using all the bootstraped values of parameters to get a bootstraped sample of the quantity of interest and then by calculating percentiles on this sample to get a confidence interval (classically 2.5 and 97.5 percentiles for a 95 percent confidence level). If CI.fill != NULL, then the whole confidence area is filled by the color CI.fill thanks to the function polygon, otherwise only borders are drawn thanks to the function matline. Further graphical arguments can be passed to these functions using the three dots arguments ....

Author(s)

Christophe Dutang and Marie-Laure Delignette-Muller.

References

Delignette-Muller ML and Dutang C (2015), fitdistrplus: An R Package for Fitting Distributions. Journal of Statistical Software, 64(4), 1-34.

See Also

See also cdfcomp, cdfcompcens, bootdist and quantile.

Examples

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# We choose a low number of bootstrap replicates in order to satisfy CRAN running times
# constraint.
# For practical applications, we recommend to use at least niter=501 or niter=1001.


# (1) Fit of an exponential distribution
#

set.seed(123)
s1 <- rexp(50, 1)
f1 <- fitdist(s1, "exp")
b1 <- bootdist(f1, niter= 11) #voluntarily low to decrease computation time

# plot 95 percent bilateral confidence intervals on y values (probabilities)
CIcdfplot(b1, CI.level= 95/100, CI.output = "probability")

# plot of the previous intervals as a band 
CIcdfplot(b1, CI.level= 95/100, CI.output = "probability", 
  CI.fill = "pink", CI.col = "red")

# plot of the previous intervals as a band without empirical and fitted dist. functions
CIcdfplot(b1, CI.level= 95/100, CI.output = "probability", CI.only = TRUE,
  CI.fill = "pink", CI.col = "red")
  
# same plot without contours
CIcdfplot(b1, CI.level= 95/100, CI.output = "probability", CI.only = TRUE,
  CI.fill = "pink", CI.col = "pink")

# plot 95 percent bilateral confidence intervals on x values (quantiles)
CIcdfplot(b1, CI.level= 95/100, CI.output = "quantile")


# plot 95 percent unilateral confidence intervals on quantiles
CIcdfplot(b1, CI.level = 95/100, CI.output = "quant", CI.type = "less", 
  CI.fill = "grey80", CI.col = "black", CI.lty = 1)
CIcdfplot(b1, CI.level= 95/100, CI.output = "quant", CI.type = "greater",
  CI.fill = "grey80", CI.col = "black", CI.lty = 1)

# (2) Fit of a normal distribution on acute toxicity log-transformed values of 
# endosulfan for nonarthropod invertebrates, using maximum likelihood estimation
# to estimate what is called a species sensitivity distribution 
# (SSD) in ecotoxicology, followed by estimation of the 5, 10 and 20 percent quantile  
# values of the fitted distribution, which are called the 5, 10, 20 percent hazardous 
# concentrations (HC5, HC10, HC20) in ecotoxicology, with their
# confidence intervals, from a small number of bootstrap 
# iterations to satisfy CRAN running times constraint and plot of the band
# representing pointwise confidence intervals on any quantiles (any HCx values)
# For practical applications, we recommend to use at least niter=501 or niter=1001.
#

data(endosulfan)
ATV <- subset(endosulfan, group == "NonArthroInvert")$ATV
log10ATV <- log10(subset(endosulfan, group == "NonArthroInvert")$ATV)
fln <- fitdist(log10ATV, "norm")
bln <- bootdist(fln, bootmethod ="param", niter=101)
quantile(bln, probs = c(0.05, 0.1, 0.2))
CIcdfplot(bln, CI.output = "quantile", CI.fill = "lightblue", CI.col = "blue",
          xlim = c(1,5))


# (3) Same type of example as example (2) from ecotoxicology
# with censored data
#
data(salinity)
log10LC50 <-log10(salinity)
fln <- fitdistcens(log10LC50,"norm")
bln <- bootdistcens(fln, niter=101)
(HC5ln <- quantile(bln,probs = 0.05))
CIcdfplot(bln, CI.output = "quantile", CI.fill = "lightblue", CI.col = "blue",
    xlab = "log10(LC50)",xlim=c(0.5,2),lines01 = TRUE)
# zoom around the HC5  
CIcdfplot(bln, CI.output = "quantile", CI.fill = "lightblue", CI.col = "blue",
          xlab = "log10(LC50)", lines01 = TRUE, xlim = c(0.8, 1.5), ylim = c(0, 0.1))
abline(h = 0.05, lty = 2) # line corresponding to a CDF of 5 percent

fitdistrplus documentation built on May 28, 2021, 9:06 a.m.