mlebme {irtoys}R Documentation

Maximum likelihood and Bayes Modal estimation of ability

Description

Estimates the value of the latent variable ("ability") for each person by direct optimization

Usage

mlebme(resp, ip, mu=0, sigma=1, method="ML")

Arguments

resp A matrix of responses: persons as rows, items as columns, entries are either 0 or 1, no missing data
ip Item parameters: a matrix with one row per item, and three columns: [,1] item discrimination a, [,2] item difficulty b, and [,3] asymptote c.
mu Mean of the apriori distribution. Ignored when method="ML". Default is 0.
sigma Standard deviation of the apriori distribution. Ignored when method="ML". Default is 1.
method "ML" for maximum likelihood or "BM" for Bayes Modal estimation. Default is "ML", in which case any values for mu and sigma will be ignored.

Value

A matrix with the ability estimates in column 1 and their standard errors of measurement (SEM) in column 2

Author(s)

Ivailo Partchev

See Also

eap

Examples

data(Scored)
p.2pl  <- est(Scored, model="2PL", engine="ltm")
th.mle <- mlebme(resp=Scored, ip=p.2pl)

[Package irtoys version 0.1.1 Index]