  </td>
        <td><p>S3 Method for Computing Observed and Expected Frequencies of Univariate and
Bivariate Marginals</p></td>
      </tr><tr><td>
          <p><code><a href="IRT.IC.html">IRT.IC()</a></code> </p>
        </td>
        <td><p>Information Criteria</p></td>
      </tr><tr><td>
          <p><code><a href="IRT.irfprob.html">IRT.irfprob()</a></code> </p>
        </td>
        <td><p>S3 Methods for Extracting Item Response Functions</p></td>
      </tr><tr><td>
          <p><code><a href="IRT.irf