Calculate Test Information For eRm objects
Calculates the information of a test or a scale as the sum of Samejima's (1969) information for all items.
test_info(ermobject, theta=seq(-5,5,0.01))
ermobject |
An object of class |
theta |
Supporting or sampling points on the latent trait. |
The function test_info
calculates the test or scale information of the
whole set of items in the 'eRm'
object.
Returns the vector of test information for all values of theta.
Thomas Rusch
Samejima, F. (1969) Estimation of latent ability using a response pattern of graded scores. Psychometric Monographs, 17.
res <- PCM(pcmdat) tinfo <- test_info(res) plotINFO(res, type="test")
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