Description Usage Arguments Value Examples
Function generates categorical data 1...5 for N
persons and J
items given the item parameters betas
.
1 2 3 |
N |
number of persons |
J |
number of items |
betas |
Jx3 matrix with item parameters on three response dimensions
(middle, extreme, target trait defined by |
traitItem |
vector of length J specifying the underlying traits (e.g., indexed from 1...5). Standard: only a single trait is measured by all items. If the Big5 are measured, might be something like c(1,1,1,2,2,2,...,5,5,5,5) |
theta_vcov |
3x3 covariance matrix for middle, extremity, trait(s) (can be a vector of length 3 with variances for uncorrelated processes). |
prop.rev |
proportion of reversed items (rounded to next integer). Can
be a vector if multiple traits are specified by |
revItem |
vector of length J specifying reversed items (1=reversed, 0=regular) |
cat |
whether to return categorical data (response categories 1...5) or multinomial data (frequencies of 0 and 1) |
The function returns a list containing the generated matrix of responses X, a vector revItem indicating reversed items and true, latent values of the parameters.
1 2 3 4 | N <- 20
J <- 10
betas <- cbind(rnorm(J, .5), rnorm(J, .5), rnorm(J, 0))
dat <- generate_irtree_2012(N = N, J = J, betas = betas)
|
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