catSurv (version 1.3.0)

expectedPV: Expected Posterior Variance

Description

Estimates the expected posterior variance for a respondent's estimated ability parameter for an item yet to be answered based on a respondent's ability parameter estimate from the already-answered items.

Usage

expectedPV(catObj, item)

Arguments

catObj

An object of class Cat

item

An integer indicating the index of the question item

Value

The function expectedPV returns a numeric value indicating a respondent's expected posterior variance for an unasked item.

See Also

estimateSE, probability, selectItem

Examples

# NOT RUN {
## Loading ltm Cat object
data(ltm_cat)

## Store example answers
setAnswers(ltm_cat) <- c(1,0,1,0,1, rep(NA, 35))

## Estimate EPV for different unasked items
expectedPV(ltm_cat, item = 10)
expectedPV(ltm_cat, item = 20)
expectedPV(ltm_cat, item = 30)


# }