regDIF (version 1.1.1)

d_sigma_gaussian: Partial derivatives for variance parameter of continuous items.

Description

Partial derivatives for variance parameter of continuous items.

Usage

d_sigma_gaussian(
  parm,
  p_item,
  etable,
  theta,
  responses_item,
  pred_data,
  cov,
  samp_size,
  num_items,
  num_quad
)

Value

a "list" of first and second partial derivatives for variance value of Gaussian item likelihood (to use with coordinate descent and univariate Newton-Raphson)

Arguments

parm

Item parameter being maximized.

p_item

Vector of item parameters.

etable

E-table for impact.

theta

Matrix of adaptive theta values.

responses_item

Vector of item responses.

pred_data

Matrix or dataframe of DIF and/or impact predictors.

cov

Covariate being maximized.

samp_size

Sample size in dataset.

num_items

Number of items in dataset.

num_quad

Number of quadrature points used for approximating the latent variable.