mean,Item-method {irt}

Calculate the expected value of an Item

Description

mean Returns the expected value of an item for given parameters for a given ability or abilities, i.e. \theta.

Usage

## S4 method for signature 'Item'
mean(x, ...)

## S4 method for signature 'Rasch'
mean(x, ...)

## S4 method for signature '1PL'
mean(x, ...)

## S4 method for signature '2PL'
mean(x, ...)

## S4 method for signature '3PL'
mean(x, ...)

## S4 method for signature '4PL'
mean(x, ...)

## S4 method for signature 'GPCM'
mean(x, ...)

## S4 method for signature 'GPCM2'
mean(x, ...)

## S4 method for signature 'GRM'
mean(x, ...)

## S4 method for signature 'PCM'
mean(x, ...)

Arguments

x

An Item-class object containing the item parameters.

...

Additional parameters. Specifically theta argument is required. theta should be a numeric vector of ability parameters.

Value

Item expected values at given theta(s) values will be returned.

Author(s)

Emre Gonulates

Examples

itm <- generate_item(model = "Rasch")
mean(itm, theta = 1)
mean(itm, -1.2)

itm <- generate_item(model = "GPCM", n_categories = 5)
mean(itm, theta = 1.5)
mean(itm, 0.2)