IIF3PLM {exametrika}R Documentation

IIF for 3PLM

Description

Item Information Function for 3PLM

Usage

IIF3PLM(a, b, c, theta)

Arguments

a

slope parameter

b

location parameter

c

lower asymptote parameter

theta

ability parameter

Value

Returns a numeric vector representing the item information at each ability level theta. The information is calculated as: I(\theta) = \frac{a^2(1-P(\theta))(P(\theta)-c)^2}{(1-c)^2P(\theta)}


[Package exametrika version 1.1.0 Index]