pairwise (version 0.1.5)

thetaML.dicho: ML Theta Parameter dichotomous 1PL

Description

Calculation of the theta person parameter for dichotomous items, given the item parameters and one respose vector according the 1PL Rasch Model using an ML approach.

Usage

thetaML.dicho(response, sigma, na_treat = 0,
    theta_init = log(sum(response, na.rm = TRUE)),
    limit = 1e-05, iter = 20)

Arguments

response

numeric vector with responses of a person coded in the (0,1) manner.

sigma

numeric vector with item (difficulty) parameters.

na_treat

numeric defining the type of treatment to missing responses in the argument response. If set to na_treat=0 (default) missing responses are treated as wrong answers. An option is to set na_treat to any value b

theta_init

numeric giving the startvalue for estimation of theta. Default is log() of the persons rawscore (while NAs are removed for rawscore calculation).

limit

numeric giving the limit at which accuracy the ML-algorithm stops.

iter

numeric giving the maximum numer of iteration to perform.

Value

• An object of class thetaMLdicho containing the person parameter.

Details

as this function is usualy not called directly by the user, there are no checks for plausibillity of the arguments !. Instead of calling this function directly, consider using the function ppML.dicho.

Examples

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