scp {irtoys}

Plot observed and predicted scores against ability

Description

Produces a plot of IRT true scores (test response function at the estimated ability) with a confidence band (plus/minus standard error). The observed sum scores are shown in red.

Usage

scp(resp, ip, theta = NULL)

Arguments

resp

A matrix of binary responses to a test, with persons as rows and items as columns.

ip

Item parameters: the output of est, or a 3-column matrix corresponding to its first element, est.

theta

An object containing ability estimates, as output by function mlebme or eap. If NULL, MLE will be estimated from resp and ip.

Value

None

Author(s)

Ivailo Partchev

See Also

mlebme, eap, tsc, trf

Examples

scp(Scored, Scored2pl)