Description Usage Arguments Value See Also Examples
The probability function in the 2PL model.
1 | probability.2pl(z, a = z$a, b = z$b, theta, d = -a * b)
|
z |
Optional. A list with the parameters a and b specified by keys. |
a |
The discrimination parameter |
b |
The difficulty parameter. (Optional if d is specified) |
theta |
The subject's latent trait. |
d |
Optional. Overrides the b parameter, it is equal to -a*b. Used in some functions. |
Tue value of the probability for the model 2pl.
probability.1pl
, probability.3pl
,
prob.3pl
, prob.2pl
1 2 3 4 5 6 7 8 | ## Simulate the test
# data <- simulateTest(model = "2PL", items = 20, individuals = 200)
## item parameters
# zita <-data$itempars
## Latent traits
# thetas <- data$latentTraits
## Probability model
# probability.2pl(zita, theta = thetas)
|
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