Summarize response data as expected quadrature counts — summarize_expected

Converts response data and posterior quadrature weights into Bock-Aitkin style expected counts. For each item and quadrature node, N is the expected number of observed responses and R is the expected number correct.

Usage

summarize_expected_counts(resp, weights)

Arguments

resp: A response matrix with rows for subjects and columns for items.
weights: Posterior quadrature weights, usually returned by posterior_weights_2pl().

Value

A list of class "mixedsubjects_counts" containing matrices N and R, sample size n, quadrature nodes, quadrature weights, and item names.

Examples

pars <- data.frame(a = c(1, 1.2), d = c(0, -0.5))
resp <- matrix(c(1, 0, 0, 1), nrow = 2, byrow = TRUE)
W <- posterior_weights_2pl(resp, pars, n_quad = 5)
counts <- summarize_expected_counts(resp, W)
counts$N
#>             node1     node2    node3     node4       node5
#> Item1 0.003717598 0.2836301 1.312301 0.3944443 0.005906825
#> Item2 0.003717598 0.2836301 1.312301 0.3944443 0.005906825