PlotProbDist: Plot Probability Distribution

In DescTools: Tools for Descriptive Statistics

Plot Probability Distribution

Description

Produce a plot from a probability distribution with shaded areas. This is often needed in theory texts for classes in statistics.

Usage

PlotProbDist(breaks, FUN, 
             blab = NULL, main = "", xlim = NULL, col = NULL, density = 7, 
             alab = LETTERS[1:(length(breaks) - 1)], 
             alab_x = NULL, alab_y = NULL, ylab = "density", ...)

Arguments

breaks	a numeric vector containing the breaks of different areas. The start and end must not be infinity.
FUN	the (typically) distribution function
blab	text for labelling the breaks
main	main title for the plot
xlim	the x-limits for the plot
col	the color for the shaded areas
density	the density for the shaded areas
alab	the labels for areas
alab_x	the x-coord for the area labels
alab_y	the y-coord for the area labels, if left to default they will be placed in the middle of the plot
ylab	the label for they y-axis
...	further parameters passed to internally used function curve()

Details

The function sets up a two-step plot procedure based on curve() and Shade() with additional labelling for convenience.

Value

nothing returned

Author(s)

Andri Signorell <[e-mail]>

See Also

Shade, curve, polygon

Examples

# plot t-distribution
PlotProbDist(breaks=c(-6, -2.3, 1.5, 6), 
             function(x) dt(x, df=8), 
             blab=c("A","B"), xlim=c(-4,4), alab=NA,
             main="t-Distribution (df=8)",
             col=c(DescTools::hred, DescTools::hblue, DescTools::horange), 
             density=c(20, 7))

# Normal
PlotProbDist(breaks=c(-10, -1, 12), 
             function(x) dnorm(x, mean=2, sd=2), 
             blab="A", xlim=c(-7,10),
             main="Normal-Distribution N(2,2)",
             col=c(DescTools::hred, DescTools::hblue), density=c(20, 7))

# same for Chi-square
PlotProbDist(breaks=c(0, 15, 35), 
             function(x) dchisq(x, df=8), 
             blab="B", xlim=c(0, 30),
             main=expression(paste(chi^2-Distribution, " (df=8)")),
             col=c(DescTools::hblue, DescTools::hred), density=c(0, 20))

DescTools documentation built on April 4, 2025, 1:55 a.m.