rpf (version 0.5)

rpf.sample: Randomly sample response patterns given a list of items

Description

Returns a random sample of response patterns given a list of item models and parameters.

Usage

rpf.sample(theta, items, params, design)

Arguments

theta

either a vector of trait abilities or the number of abilities to draw from N(0,1)

items

a list of item models

params

a list of item parameters. If omitted, random item parameters are generated for each item model.

design

assigns person abilities to item dimensions

Value

• Returns a matrix of response patterns

See Also

sample

Examples

# 1 dimensional items
i1 <- rpf.drm()
i1.p <- rpf.rparam(i1)
i2 <- rpf.gpcm(numOutcomes=3)
i2.p <- rpf.rparam(i2)
rpf.sample(5, list(i1,i2), list(i1.p, i2.p))

# multidimensional items
numItems <- 4
items <- vector("list", numItems)
correct <- vector("list", numItems)

i1 <- rpf.drm(dimensions=2)
i2 <- rpf.drm(dimensions=1, multidimensional=TRUE)

for (ix in 1:(numItems-1)) {
  items[[ix]] <- i1
  correct[[ix]] <- rpf.rparam(i1)
}
items[[4]] <- i2
correct[[4]] <- rpf.rparam(i2)

design <- matrix(c(1, 1, 1, 1,
                   2, 2, 3, NA), nrow=2, byrow=TRUE)
rpf.sample(10, items, correct, design)