iccplot {birtr} | R Documentation |

## 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)
```

[Package

*birtr*version 1.0.0 Index]