     <td><p>Logical. Should an identity line be used as the reference
line? If <code>TRUE</code>, the identity line is used. If <code>FALSE</code> (default),
the commonly-used Q-Q line that intercepts two data quantiles specified in
<code>qprobs</code> is used. Please notice that the chosen reference line will
also be used for the detrending procedure, if <code>detrend = TRUE</code>.</p></td>
    </tr>
    <tr>
      <th>qtype</th>
      <td><p>Integer between 1 and 9. Only used if <code>detrend = TRUE</cod