gamma_matrix: Gammas of item.parameters given total score using matrix...

In jeppebundsgaard/RDigram: Analysis of Items from Tests and Surveys

Gammas of item.parameters given total score using matrix calculations

Description

Gammas of item.parameters given total score using matrix calculations

Usage

gamma_matrix(
  item.params = NULL,
  param.type = c("multiplicative", "pcm", "log.item.score", "xsi"),
  R = NULL
)

Arguments

item.params	a matrix of item parameters (using the PCM parametrisation). Items in rows, threshold values in columns
param.type	Type of item parameters given. One of pcm (RUMM2030), log.item.score (?), multiplicative (DIGRAM or RDigram, xsi (Conquest or TAM))
R	The total score for which to calculate the gamma parameter (set to NULL to get gammas for all possible total scores)

Details

Always use gamma.matrix instead of gamma.pattern. It is far more efficient.

Value

Returns gamma for the given total score.

Author(s)

Jeppe Bundsgaard & Svend Kreiner

References

Jeppe Bundsgaard & Svend Kreiner (2019). Undersøgelse af De Nationale Tests måleegenskaber. 2nd Ed. Copenhagen: DPU, Aarhus University.

Examples

item.params<-matrix(c(1,.5,1,1,1,2,1,4),nrow=4)
gamma.matrix(item.params,"multiplicative",3)

jeppebundsgaard/RDigram documentation built on Oct. 29, 2023, 7:15 p.m.