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Calculates a matrix of item response probabilities over a grid of theta values for an item
probgrm(theta, a, cb)
Returns a matrix of item response probabilities. The first dimension corresponds to the length of theta.
a vector of theta values (e.g., quadrature points)
a slope parameter value
a vector of category threshold values
Seung W. Choi <choi.phd@gmail.com>
The Graded Response Model (Samejima, 1969) is assumed.
Samejima, F. (1969). Estimation of latent ability using a response pattern of graded scores. Psychometrika Monograph, 17.
calcprob, probgpcm
calcprob
probgpcm
probgrm(seq(-4,4,.1), 1.5, c(-1.2,0.5,1.5))
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