TestInformationFunc: TIF for IRT
Description
Test Information Function for 4PLM
Usage
TestInformationFunc(params, theta)
Value
Returns a numeric vector representing the test information at each ability
level theta. The test information is the sum of item information functions for
all items in the test: \(I_{test}(\theta) = \sum_{j=1}^n I_j(\theta)\)
Arguments
- params
parameter matrix
- theta
ability parameter