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Last data update: 2014.03.03

R: Maximum likelihood and Bayes Modal estimation of ability

mlebme

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, and the number of non-missing responses in column 3

Author(s)

Ivailo Partchev

Examples

th.mle <- mlebme(resp=Scored, ip=Scored2pl$est)