mirt (version 1.17.1)

probtrace: Function to calculate probability trace lines

Description

Given an internal mirt object extracted from an estimated model compute the probability trace lines for all categories.

Usage

probtrace(x, Theta)

Arguments

x

an extracted internal mirt object containing item information (see extract.item)

Theta

a vector (unidimensional) or matrix (unidimensional/multidimensional) of latent trait values

See Also

extract.item

Examples

mod <- mirt(Science, 1)
extr.2 <- extract.item(mod, 2)
Theta <- matrix(seq(-4,4, by = .1))
traceline <- probtrace(extr.2, Theta)

head(data.frame(traceline, Theta=Theta))