CAT_ability_est {cat.dt}

R Documentation

Ability level estimation for an individual using a CAT decision tree

Description

Computes the test taker's estimated ability level based on the CAT decision tree previously built and the test taker's responses to every item at every tree level

Usage

CAT_ability_est(cat.dt, res)

Arguments

cat.dt	A cat.dt object returned by CAT_DT.
res	Vector containing the test taker's responses to every item

Value

A list containing the following elements:

$estimation Estimated ability level after each level of the tree.

$linf Lower limit of the final estimation at 95

$lsup Upper limit of the final estimation at 95

$items Administered item in each level.

$graphics Plot object of the evolution of the ability level estimation. It shows the ability level estimation after the individual has answered to every administered item.

Author(s)

Javier Rodr?guez-Cuadrado

Examples

data("itemBank")
# Build the cat.dt
nodes = CAT_DT(bank = itemBank, model = "GRM", crit = "MEPV",
               C = 0.3, stop = c(3,0.5), limit = 200, inters = 0.98,
               p = 0.9, dens = dnorm, 0, 1)

# Estimate the ability level of a subject with responses res
estimation = CAT_ability_est(nodes, res = itemRes[1, ])

#plot the estimations
plot(estimation$graphics)

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