mirt (version 0.6.0)

probtrace: Function to calculate probability trace lines

Description

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

Usage

probtrace(x, Theta)

Arguments

x

an extracted internal mirt object containing item information

Theta

a matrix of latent trait values

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))