eRm (version 1.0-9)

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))

Value

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

Arguments

ermobject

An object of class 'eRm'.

theta

Supporting or sampling points on the latent trait.

Author

Thomas Rusch

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")