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

resp

Item parameters: a matrix with one row per
  item, and three columns: [,1] item discrimination
  $a$, [,2] item difficulty $b$, and [,3] asymptote
  $c$.

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

Provides 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, and a variety of functions useful with IRT models.

scp: Plot observed and predicted scores against ability

Description

Usage

Arguments

Value

See Also

Examples