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Last data update: 2014.03.03

R: True scores with standard errors

tsc	R Documentation

True scores with standard errors

Description

Computes the IRT true scores (test response function at the estimated ability) and an estimate of their standard error via the delta theorem, treating item parameters as known).

Usage

  tsc(ip, theta)

Arguments

`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.
`theta`	An object containing ability estimates, as output by function `mlebme` or `eap`

Value

A matrix with the true scores in column 1, and their standard errors of measurement (SEM) in column 2

Author(s)

Ivailo Partchev

Examples

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