Modified from the package `irtoys`

.

1 2 3 4 5 6 7 |

`ip` |
A Jx3 matrix of item parameters. Columns are discrimination, difficulty, and guessing |

`x` |
Vector of theta points |

`resp` |
Response data matrix, subjects by items |

`min, max` |
MLE is undefined for perfect scores. These parameters define the range in which to search for the MLE, if the score is perfect, the min or max will be returned. |

`n` |
Number of quadrature points wanted |

`lower, upper` |
Range of points wanted |

`mu, sigma` |
The normal distribution from which points and weights are taken |

`D` |
The scaling constant for the IRT parameters, defaults to 1.7, alternatively often set to 1. |

`iif`

gives item information, `irf`

gives item response function, `MLE`

returns maximum likelihood estimates of theta (perfect scores get +-4), `normal.qu`

returns a list length 2 of normal quadrature points and weights, `SEM`

gives the standard error of measurement at the given ability points, `sim`

returns simulated response matrix, `tif`

gives the test information function.

Quinn N. Lathrop

Partchev, I. (2014) irtoys: Simple interface to the estimation and plotting of IRT models. R package version 0.1.7.

1 2 3 4 5 6 7 8 9 10 |

Questions? Problems? Suggestions? Tweet to @rdrrHQ or email at ian@mutexlabs.com.

All documentation is copyright its authors; we didn't write any of that.