| iccplot {birtr} | R Documentation |
Plots an item characteristic curve under the two-parameter logistic model.
iccplot(b, a)
b |
a single number representing the value of item difficulty. |
a |
a single number representing the value of item discrimination. |
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.
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
iccplot(0, 1) iccplot(a = 1, b = 0) iccplot(0, 1); par(new = TRUE); iccplot(-1.5, 1)