TestDesign (version 1.7.0)

calc_posterior_function: Calculate a posterior distribution of theta

Description

Calculate a posterior distribution of theta.

Usage

calc_posterior_function(
  theta_grid,
  item_parm,
  resp,
  ncat,
  model,
  prior,
  prior_parm
)

Arguments

theta_grid

An equi-spaced grid of theta values.

item_parm

A numeric matrix of item parameters.

resp

a numeric vector containing item responses.

ncat

A numeric vector of the number of response categories by item.

model

A numeric vector indicating the IRT models of each item (1: 1PL, 2: 2PL, 3: 3PL, 4: PC, 5: GPC, 6: GR).

prior

The type of prior distribution (1: normal, 2: uniform).

prior_parm

A numeric vector of hyperparameters for the prior distribution, c(mu, sigma) or c(ll, ul).