setup.hypothesis {irtpwr}

Setup null and alternative hypothesis

Description

Setup null and alternative hypothesis

Usage

setup.hypothesis(type, altpars = NULL, nullpars = NULL)

Arguments

type

preset, e.g. '1PLvs2PL'. Either a string for an existing preset or a list with the required functions for a custom preset. See the section extending the package for a tutorial on how to create a custom preset.

altpars

List of model parameters following the alternative hypothesis. The format depends on the preset. When parameters are derived from observed data by mirt, the coef_short function can be used to convert the parameters to the right format.

nullpars

List of model parameters following the null hypothesis. The format depends on the preset. Null parameters are not necessary for some hypothesis presets, e.g. 1PLvs2PL.

Value

a list specifying the hypothesis for usage in further functions, e.g. estimation of the noncentrality parameters.

Examples

library(mirt)
dat <- expand.table(LSAT7)
mirtfit <- mirt(dat,1,verbose = FALSE)
hyp <- setup.hypothesis(type = '1PLvs2PL', altpars = mirtfit)