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exametrika (version 1.1.0)

IIF2PLM: IIF for 2PLM

Description

Item Information Function for 2PLM

Usage

IIF2PLM(a, b, theta)

Value

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

Arguments

a

slope parameter

b

location parameter

theta

ability parameter