vcov,DiscreteClass-method

vcov,MixedClass-method

vcov,MultipleGroupClass-method

vcov,SingleGroupClass-method

vcov-method

an object of class <code>SingleGroupClass</code>,
<code>MultipleGroupClass</code>, or <code>MixedClass</code>

object

Extract parameter variance covariance matrix

Analysis of dichotomous and polytomous response data using
    unidimensional and multidimensional latent trait models under the Item
    Response Theory paradigm. Exploratory and confirmatory models can be
    estimated with quadrature (EM) or stochastic (MHRM) methods. Confirmatory
    bi-factor and two-tier analyses are available for modeling item testlets.
    Multiple group analysis and mixed effects designs also are available for
    detecting differential item and test functioning as well as modelling
    item and person covariates.

vcov-method: Extract parameter variance covariance matrix

Description

Usage

Arguments

Examples