prob.2pl: 2PL fast probability function

In IRTpp: Estimating IRT Parameters using the IRT Methodology

Description

The probability function in the 2PL model.

Usage

prob.2pl(z, theta)

Arguments

z	List containing the item parameters a and d
theta	Vector, contains the latent traits of the individual

Value

The value of the probability for the 2PL model.

See Also

probability.2pl, prob.3pl, probability.3pl, probability.1pl

Examples

## Simulate the test
# data <- simulateTest(model = "2PL", items = 20, individuals = 200)
## item parameters
# zita <-data$itempars
# zita <- list(zita$a, zita$b, zita$c)
## transformation of the parameter b
# zita <- model.transform(zita, model = "3PL", src = "b", target = "d")
# zita <- list(a = zita[,1], d = zita[,1], c = zita[,1])
## Latent traits
# thetas <- data$latentTraits
## Probability model
# prob.2pl(zita, thetas)

IRTpp documentation built on May 29, 2017, 9:58 a.m.