irtoys (version 0.1.5)

plot.trf: A plot method for test response functions

Description

Useful for plotting test response functions. The x argument of trf should better be left out unless something special is required.

Usage

## S3 method for class 'trf':
plot(x, add = FALSE, main = "Test response function", co = 1, ...)

Arguments

x

An object produced by function trf

add

When add=T, the IRF is added to a plot, otherwise a new plot is started. Default is F.

main

The main title of the plot, given that add=F.

co

The colour of the TRF curve. Default is 1 for black. Use co=NA to plot each TRF in a different colour.

...

Any additional plotting parameters

See Also

trf

Examples

p.2pl <- est(Scored, model = "2PL", engine = "ltm")
plot(trf(p.2pl))