scp function

Plot observed and predicted scores against ability

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.

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.

Returns

None

Examples

scp(Scored, Scored2pl)

See Also

mlebme, eap, tsc, trf

Author(s)

Ivailo Partchev