qrs function

Quantiles of the ranked sum scores

A rough estimate of the values of the latent variable ("ability"). The sum scores (number of correct responses) are ranked, breaking ties at random. The ranks are divided by the sample size + 1, and the corresponding quantiles of the standard Normal distribution are returned. Used as default in the non-parametric IRF plots produced by npp in analogy to Jim Ramsay's TestGraf. Another possible use is in itf.

qrs(resp)

Arguments

• resp: A matrix of responses: persons as rows, items as columns, entries are either 0 or 1, no missing data

Returns

A one-column matrix of values

Examples

sc <- qrs(Scored)

See Also

npp, itf

Author(s)

Ivailo Partchev