ItemInformationFunc {exametrika} | R Documentation |
IIF for 4PLM
Description
Item Information Function for 4PLM
Usage
ItemInformationFunc(a = 1, b, c = 0, d = 1, theta)
Arguments
a |
slope parameter |
b |
location parameter |
c |
lower asymptote parameter |
d |
upper asymptote parameter |
theta |
ability parameter |
Value
Returns a numeric vector representing the item information at each ability level theta. The information is calculated based on the first derivative of the log-likelihood of the 4PL model with respect to theta.
[Package exametrika version 1.1.0 Index]