dlogL: First derviative of log-likelihood of 2PL, in theta.

Description Usage Arguments Value

View source: R/IRF_functions.R

Description

Used to estimate theta in est_2PL.

Usage

1
dlogL(resp, parms, theta)

Arguments

resp

a matrix or data.frame containing the binary item responses.

parms

a named list or data.frame with elements parms$alpha and parms$beta corresponding to the discrimination and difficulty parameters of the 2PL model, respectively.

theta

the latent trait.

Value

length(theta)- vector of first derivatives of log-likelihood of 2PL, in theta.


peterhalpin/cirt documentation built on July 15, 2018, 12:42 p.m.