Plot Probability Distribution

Produces a plot of a probability distribution function with shaded areas. Useful for illustrating critical regions, p-values, or probability masses in statistics teaching materials.

Usage

plotProbDist(
  breaks,
  FUN,
  main = NULL,
  ylab = "density",
  xlim = NULL,
  col = NULL,
  density = 7,
  grid = .useTheme,
  box = .useTheme,
  areaLabels = NULL,
  breakLabels = NULL,
  stamp = .useTheme,
  ...
)

Arguments

breaks: numeric vector of break points defining the boundaries between shaded areas. The first and last value define the plot range passed to shade(); interior values are the actual boundaries.
FUN: the distribution density function to plot, typically of the form function(x) dnorm(x, mean=0, sd=1).
main: main title. NULL (default) draws none, unless the theme sets autoTitle = TRUE (see theme); the title is then derived from the expression passed as FUN. "", NA or FALSE always suppress it and compact the top margin; any other string is used as given.
ylab: label for the y-axis. Default is "density".
xlim: numeric vector of length 2. x-axis limits passed to curve().
col: color(s) for the shaded areas. Recycled if shorter than the number of areas. Defaults to the "helsana" palette.
density: density of shading lines passed to shade(). Default is 7.
grid: controls the background grid. .useTheme (default) follows the active theme, TRUE draws it, FALSE, NULL or NA suppress it. A named list overrides individual arguments passed to grid().
box: controls the plot box. .useTheme (default) uses the current theme setting. TRUE/FALSE forces the box on or off. A named list overrides individual arguments passed to box().
areaLabels: controls labels placed in the centre of each shaded area. NULL (default) suppresses labels. TRUE uses LETTERS as default labels. A character vector sets explicit labels. A named list overrides individual arguments passed to boxedText() (e.g. list(cex = 3) or list(x = c(-2, 3), y = 0.1) for manual positioning).
breakLabels: controls labels placed on the x-axis at interior break points via mtext(). NULL (default) suppresses labels. TRUE uses LETTERS as default labels. A character vector sets explicit labels. A named list overrides individual arguments (e.g. list(cex = 1.8, font = 1)).
stamp: controls the corner stamp. .useTheme (default) resolves to getTheme()$stamp. TRUE/FALSE/ NULL, a string, or a named list for stamp().
...: further graphical parameters passed to curve() and .applyParFromDots(), e.g. las, col.axis.

Value

NULL, invisibly.

Examples

# Normal distribution with two areas
plotProbDist(breaks = c(-10, -1, 12),
             FUN    = function(x) dnorm(x, mean = 2, sd = 2),
             main   = "Normal-Distribution N(2,2)",
             xlim   = c(-7, 10),
             col    = c("deeppink4", "skyblue3"),
             density = c(20, 7),
             breakLabels = TRUE)


# t-distribution with three areas
plotProbDist(breaks = c(-6, -2.3, 1.5, 6),
             FUN    = function(x) dt(x, df = 8),
             main   = "t-Distribution (df=8)",
             xlim   = c(-4, 4),
             col    = c("deeppink4", "skyblue3", "darkorange2"),
             density = c(20, 7),
             areaLabels = FALSE,
             breakLabels = list(text=c("A", "B")))


# Chi-square distribution
plotProbDist(breaks  = c(0, 15, 35),
             FUN     = function(x) dchisq(x, df = 8),
             main    = expression(chi^2~"-Distribution (df=8)"),
             xlim    = c(0, 30),
             col     = c("deeppink4", "skyblue3"),
             density = c(0, 20),
             breakLabels = list(text="B"))

Usage

Arguments

Value

See also

Examples