Description Usage Arguments Value Author(s)
Calculates the differences between two item option characteristic curves for all options (minus one).
1 2 3 4 5 6 | CalculateItemDifferences(
thetaValue,
itemParameters,
irtModel = "2pl",
logistic = TRUE
)
|
thetaValue |
A numeric value or array for the theta (ability) value(s) for which the difference will be calculated |
itemParameters |
A list containing "focal" and "reference" item parameters. Item parameters are assumed to be on the same scale. Item parameters for each group should me a matrix with nrow equal to the number of items. |
irtModel |
A string stating the irtModel to be used. Should be one of "1pl", "2pl", "3pl", "grm" or "pcm". |
logistic |
A logical value stating if the IRT model will use the logistic or the normal metric. |
difference A numeric matrix with the differences on probabilities or on expected score for each item between focal and reference groups.
Victor H. Cervantes <vhcervantesb at unal.edu.co>
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.