TRF for IRT

Calculates the expected score across all items on a test for a given ability level (theta) using Item Response Theory. The Test Response Function (TRF) is essentially the sum of the Item Characteristic Curves (ICCs) for all items in the test.

Usage

TestResponseFunc(params, theta)

Arguments

params

parameter matrix

theta

ability parameter

Value

A numeric vector with the same length as theta, containing the expected total score for each ability level.

Details

The Test Response Function computes the expected total score for an examinee with a given ability level (theta) across all items in the test. For each item, the function uses the logistic model with parameters a (discrimination), b (difficulty), c (guessing), and d (upper asymptote).