Item Characteristic Curve Fitting
Plots the item characteristic curve and the simulated observed proportions of correct response from the one-, two-, or three-parameter logistic model.
iccfit(mdl)
mdl |
1, 2, or 3 representing the number of the model parameters. |
While the theoretical range of ability is from negative infinity to positive
infinity, practical considerations usually limit the range of values
from -3 to +3.
With the number of item characteristic curve model parameters mdl
the item parameters are randomly sampled from the uniform distributions; for
example, under the three-parameter logistic model, b from the -3 to
3 range, a from the 0.2 to 2.8 range, and c from the 0 to
.35 range.
Each of the 33 ability levels from the -3 to +3 range with .1875 interval,
the observed proportion of correct response is generated from the binomial
distribution for sample size of 21.
The chi-square goodness-of-fit index is obtained and reported with the
set of item parameters.
Baker, F. B., & Kim, S.-H. (2017). The basics of item response theory using R. New York, NY: Springer. ISBN-13: 978-3-319-54204-1
iccfit(1) iccfit(2) iccfit(3)
Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.