 prior normal mean of the association term in
the combined efficacy-toxicity model. A number. You should prioritise
specifying this value via <code>priors</code> but this option is provided for
backwards-compatibility.</p></td>
    </tr>
    <tr>
      <th>psi_sd</th>
      <td><p>Optional, the prior normal standard deviation of the
association term in the combined efficacy-toxicity model. A number. You
should prioritise specifying this value via <code>priors</code> but this option is
provided for backwards