raschmix-methods {psychomix}

Methods for raschmix Objects

Description

Methods for raschmix-class objects.

Usage

## S4 method for signature 'raschmix'
summary(object, eps = 1e-4, ...)

## S4 method for signature 'raschmix'
parameters(object,
       which = c("model", "item", "score", "concomitant"),
       difficulty = TRUE, component = NULL, simplify = TRUE)

## S4 method for signature 'raschmix'
worth(object, difficulty = TRUE, component = NULL)

## S4 method for signature 'raschmix'
itempar(object, ref = NULL, alias = TRUE, ...)

scoreProbs(object, component = NULL, simplify = TRUE)

Arguments

object

An object of class "raschmix".

eps

Probabilities below this threshold are treated as zero in the summary method.

which

Indicates which type of parameters are used. model refers to both item and score parameters, item and score to their corresponding parameters separately. The parameters of the concomitant model are accessed through concomitant.

difficulty

Indicates whether item difficulty (default) or easiness parameters are used.

component

Indicates which components are returned. Default is all components.

ref

a vector of labels or position indices of item parameters or a contrast matrix which should be used as restriction/for normalization. If 'NULL' (the default), all items are used (sum zero restriction).

alias

logical. If 'TRUE' (the default), the aliased parameter is included in the return vector. If 'FALSE', it is removed. If the restriction given in 'ref' depends on several parameters, the first parameter of the restriction specified is (arbitrarily) chosen to be removed if 'alias' is 'FALSE'.

simplify

Should the result be simplified if possible?

...

Currently not used.

Details

worth transforms the item parameters so that the sum over all item parameters (within each component) is zero.

itempar allows for the flexible specification of the restriction applied to the item parameters.

scoreProbs does not include any aliased parameters if a certain raw score is not present in the data.