iccplot {birtr}

Item Characteristic Curve Plot

Description

Plots an item characteristic curve under the two-parameter logistic model.

Usage

iccplot(b, a)

Arguments

b

a single number representing the value of item difficulty.

a

a single number representing the value of item discrimination.

Details

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.

References

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

Examples

iccplot(0, 1)
iccplot(a = 1, b = 0)
iccplot(0, 1); par(new = TRUE); iccplot(-1.5, 1)