eRm (version 0.15-4)

test_info: Calculate Test Information For 'eRm' objects

Description

Calculates the information of a test or a scale as the sum of Samejima's (1969) information for all items.

Usage

test_info(ermobject, theta=seq(-5,5,0.01))

Arguments

ermobject

An object of class 'eRm'.

theta

Supporting or sampling points on the latent trait.

Value

• Returns the vector of test information for all values of theta.

Details

The function test_info calculates the test or scale information of the whole set of items in the 'eRm' object.

References

Samejima, F. (1969) Estimation of latent ability using a response pattern of graded scores. Psychometric Monographs, 17.

See Also

The function to calculate the item information, item_info and the plot function plotINFO.

Examples

res <- PCM(pcmdat)
tinfo <- test_info(res)
plotINFO(res, type="test")