A matrix of binary responses to a test, with persons as rows and
items as columns.

resp

Item parameters: the output of <code>est</code>, or a 3-column matrix 
corresponding to its first element, <code>est</code>.

An object containing ability estimates, as output by function
<code>mlebme</code> or <code>eap</code>. If <code>NULL</code>, MLE will be estimated from
<code>resp</code> and <code>ip</code>.

theta

Produces a plot of IRT true scores (test response function at the estimated
ability) with a confidence band (plus/minus standard error). The observed
sum scores are shown in red.

models

A collection of functions useful in learning and practicing IRT,
which can be combined into larger programs. Provides basic CTT analysis,
a simple common interface to the estimation of item
parameters in IRT models for binary responses with three different programs
(ICL, BILOG-MG, and ltm), ability estimation (MLE, BME, EAP, WLE, plausible
values), item and person fit statistics, scaling methods (MM, MS, Stocking-Lord,
and the complete Hebaera method), and a rich array of parametric and
non-parametric (kernel) plots. Estimates and plots Haberman's interaction model
when all items are dichotomously scored.

scp: Plot observed and predicted scores against ability

Description

Usage

Arguments

Value

See Also

Examples