IIF for 2PLM

Item Information Function for 2PLM

Usage

IIF2PLM(a, b, theta)

Arguments

a

slope parameter

b

location parameter

theta

ability parameter

Value

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

Note

This function will be removed in exametrika 3.0.0. It is a special case of ItemInformationFunc, which covers the 1PL to 4PL models; use that instead.