Item Response Function for the 3PL Model
Computes the item response function for the 3PL model in the TAM package.
tam_irf_3pl(theta, AXsi, B, guess=NULL, subtract_max=TRUE)
theta |
Matrix or vector of \bold{θ} values |
AXsi |
Matrix of item-category parameters |
B |
Array containing item-category loadings |
guess |
Optional parameter of guessing parameters |
subtract_max |
Logical indicating whether numerical underflow in probabilities should be explicitly avoided |
Array containing item response probabilities arranged by the dimensions theta points \times items \times categories
## Not run: ############################################################################# # EXAMPLE 1: 2PL example ############################################################################# library(sirt) data(data.read, package="sirt") dat <- data.read #* estimate 2PL model mod <- TAM::tam.mml.2pl( resp=dat ) #* define theta vector theta <- seq(-3,3, len=41) #* compute item response probabilities probs <- TAM::tam_irf_3pl( theta=theta, AXsi=mod$AXsi, B=mod$B ) str(probs) ## End(Not run)
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