betaPlot: Beta density plot

In berryFunctions: Function Collection Related to Plotting and Hydrology

Beta density plot

Description

Quick and nice plot of beta density distribution based on just alpha and beta

Usage

betaPlot(
  shape1 = 1.5,
  shape2 = 5,
  lines = NA,
  fill = rgb(0, 0.3, 0.8, 0.4),
  cumulative = TRUE,
  mar = c(2, 3, 3, 3),
  keeppar = FALSE,
  las = 1,
  main = paste("Beta density with\nalpha =", signif(shape1, 3), "and beta =",
    signif(shape2, 3)),
  ylim = lim0(y),
  xlim = 0:1,
  ylab = "",
  xlab = "",
  type = "l",
  lty = 1,
  col = par("fg"),
  ...
)

Arguments

shape1	Alpha value as in dbeta. DEFAULT: 1.5
shape2	Beta value. DEFAULT: 5
lines	Quantiles at which vertical lines should be plotted. DEFAULT: NA
fill	Color passed to polygon. DEFAULT: rgb(0,0.3,0.8, 0.4)
cumulative	Should cumulative density distribution be added? DEFAULT: TRUE
mar	Margins for plot passed to par. DEFAULT: c(2,3,3,3)
keeppar	Should margin parameters be kept instead of being restored to previous value? DEFAULT: FALSE
las	Label orientation, argument passed to plot. DEFAULT: 1
main	main as in plot. DEFAULT: paste("Beta density with\nalpha =", shape1, "and beta =", shape2)
ylim, xlim	limit for the y and x axis. DEFAULT: lim0(y), 0:1
ylab, xlab	labels for the axes. DEFAULT: ""
type, lty, col	arguments passed to plot and lines.
...	further arguments passed to plot like lwd, xaxs, cex.axis, etc.

Details

This function very quickly plots a beta distribution by just specifying alpha and beta.

Value

None. Used for plotting.

Author(s)

Berry Boessenkool, [e-mail], July 2014

See Also

betaPlotComp, normPlot, dbeta, https://cran.r-project.org/package=denstrip, https://cran.r-project.org/view=Distributions

Examples

betaPlot()
betaPlot(2,1)
betaPlot(0.5, 2)

# beta distribution is often used for proportions or probabilities
# overview of parameters
# alpha = number of successes + 1.  beta = number of failures + 1
betaPlotComp()
# a bigger: HDI (Highest Density Interval) further to the right (1)
# b bigger: HDI more to the left (0)
# both bigger: narrower HDI, stronger peak

berryFunctions documentation built on Aug. 8, 2025, 6:18 p.m.