shadeDens {dafs}

Add a shaded region to a pdf plot

Description

Useful for shading regions of interest (critical regions perhaps) on a theoretical pdf to illustrate concepts such as P-values.

Usage

shadeDens(x0, x1, dens, col = "lightgrey", n.points  = 200,
         lty = 1,...)

Arguments

x0

A starting x-value for the region to be shaded

x1

An ending x-value for the region to be shaded

dens

A function that calculates the pdf

col

A color for the shaded region

n.points

The number of points to calculate the pdf at over the interval [x0,x1]

lty

Line type

...

Additional arguments to be fed to dens such as degrees of freedom, mean or standard deviation

Details

Adds a filled polygon to an existing pdf plot.

Author(s)

J Curran

Examples

x = seq(-4.5,4.5,by = 0.01)
plot(x, dnorm(x), type = 'l')
x0 = qnorm(0.975)
x1 = 4.5
shadeDens(x0, x1, dnorm)