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ltm (version 0.9-3)

Latent Trait Models under IRT

Description

Analysis of multivariate dichotomous and polytomous data using latent trait models under the Item Response Theory approach. It includes the Rasch, the Two-Parameter Logistic, the Birnbaum's Three-Parameter, the Graded Response, and the Generalized Partial Credit Models.

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Version

Install

install.packages('ltm')

Monthly Downloads

6,237

Version

0.9-3

License

GPL (>= 2)

Maintainer

Dimitris Rizopoulos

Last Published

December 9th, 2009

Functions in ltm (0.9-3)

Women's Mobility

Pairwise Associations between Items using a Correlation Coefficient

Latent Trait Model - Latent Variable Model for Binary Data

Area under the Test or Item Information Curves

Cronbach's alpha

Latent Trait Models for Item Response Theory Analyses

Factor Scores - Ability Estimates Plot method

vcov method for fitted IRT models

Graded Response Model - Polytomous IRT

Residuals for IRT models

testEquatingData

Prepares Data for Test Equating

Birnbaum's Three Parameter Model

Attitude Towards Abortion

Point-Biserial Correlation

Workplace Industrial Relation Survey Data

Multiple Choice Items to Binary Responses

Fitted Values for IRT model

Fit of the model on the margins

Factor Scores - Ability Estimates

Generalized Partial Credit Model - Polytomous IRT

Summary method for fitted IRT models

Person-Fit Statistics and P-values

Extract Estimated Loadings

Descriptive Statistics Plot method

The Law School Admission Test (LSAT), Section VI

Generate Random Responses Patterns under Dichotomous and Polytomous IRT models

Attitude to Science and Technology

Anova method for fitted IRT models

Descriptive Statistics

Unidimensionality Check using Modified Parallel Analysis

Plot method for fitted IRT models

Item-Fit Statistics and P-values

Goodness of Fit for Rasch Models

Attitude to the Environment