fitdistrplus (version 0.2-1)

plotdistcens: Plot of empirical and theoretical distributions for censored data

Description

Plots an empirical distribution for censored data with a theoretical one if specified.

Usage

plotdistcens(censdata,distr,para,leftNA=-Inf,rightNA=Inf,...)

Arguments

censdata

A dataframe of two columns respectively named left and right, describing each observed value as an interval. The left column contains either NA for left censored observations, the left b

distr

A character string "name" naming a distribution, for which the corresponding density function dname and the corresponding distribution function pname must be defined, or directly the density function.

para

A named list giving the parameters of the named distribution. This argument may be omitted only if distr is omitted.

leftNA

the real value of the left bound of left censored observations : -Inf or a finite value such as 0 for positive data for example.

rightNA

the real value of the right bound of right censored observations : Inf or a finite value such as a realistic maximum value.

...

further graphical arguments passed to other methods

Details

Empirical and, if specified, theoretical distributions are plotted in cdf. Data are reported directly as segments for interval, left and right censored data, and as points for non-censored data. Before plotting, observations are ordered and a rank r is associated to each of them. Left censored observations are ordered first, by their right bounds. Interval censored and non censored observations are then ordered by their mid-points and, at last, right censored observations are ordered by their left bounds. If leftNA (resp. rightNA) is finite, left censored (resp. right censored) observations are considered as interval censored observations and ordered by mid-points with non-censored and interval censored data. It is sometimes necessary to fix rightNA or leftNA to a realistic extreme value, even if not exactly known, to obtain a reasonable global ranking of observations. After ranking, each of the n observations is plotted as a point (one x-value) or a segment (an interval of possible x-values), with an y-value equal to r/n, r being the rank of each observation in the global ordering previously described.

See Also

plotdist.

Examples

# (1) Plot of an empirical censored distribution (censored data) as a CDF
#
d1<-data.frame(
left=c(1.73,1.51,0.77,1.96,1.96,-1.4,-1.4,NA,-0.11,0.55,
    0.41,2.56,NA,-0.53,0.63,-1.4,-1.4,-1.4,NA,0.13),
right=c(1.73,1.51,0.77,1.96,1.96,0,-0.7,-1.4,-0.11,0.55,
    0.41,2.56,-1.4,-0.53,0.63,0,-0.7,NA,-1.4,0.13))
plotdistcens(d1)

# (2) Plot of the same empirical distribution defining a realistic maximum value 
# for right censored values
#
plotdistcens(d1,rightNA=3)


# (3) Add the CDF of a normal distribution
#
plotdistcens(d1,"norm",para=list(mean=0.12,sd=1.4),rightNA=3)

# (4) Plot of the CDF of the same dataset after logarithmic transformation
#   and add of a lognormal distribution
#
d3<-data.frame(left=10^(d1$left),right=10^(d1$right))
plotdistcens(d3,leftNA=0)
plotdistcens(d3,"lnorm",para=list(meanlog=0.27,sdlog=3.3),leftNA=0)