icrfGn {lazy.irt}

R Documentation

Calculation of Item Response Function of Graded Response Items with Normal Ogive Model (2PNM)

Description

Calculation of Item Response Function of Graded Response Items with Normal Ogive Model (2PNM)

Usage

icrfGn(param, theta, smallP = 0, print = 0, plot = 0, debug = 0)

Arguments

param	Item Parameter Data Frame
theta	Discrete theta values
smallP	Minimum value of probability
print	= 1 to print result
plot	= 1 to plot result
debug	= 1 to print intemediate result

Details

An Example of Item Parameter datastet: maxncat = 5
Note that the subscript of the b-parameter ranges between
1 and ncat-1 (= maxscore) (We set c0=0.)

name ncat A b1 b2 b3 b4

Item1 2 1.0 0.0 . . .
Item2 2 1.0 0.0 . . .
Item3 3 1.5 -1.0 0.0 . .
Item4 4 1.5 -1.0 0.0 1.0 .
Item5 5 1.5 -1.0 0.0 1.0 2.0

Value

list
P length(theta) x sum(ncat) ICRF matrix
PP length(theta) x sum(ncat) ICBRF matrix
Pt length(theta) x nitems item response function
fromP, toP indexes of each ICRF in P
fromPP, toPP indexes of each ICBRF in PP

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