title: R: party package, ctree output - err?
body: <p>What does the statistics/number 'err' mean in ctree's output? How to retrive test statistic/p-value on the base of which the coovariate are being chosen? Thanks.</p>
  
  <pre><code>Model formula:
  Dis ~ score_final
  
  Fitted party:
  [1] root
  |   [2] score_final &lt;= 521
  |   |   [3] score_final &lt;= 445: 0.512 (n = 123, err = 30.7)
  |   |   [4] score_final &gt; 445: 0.358 (n = 684, err = 157.2)
  |   [5] score_final &gt; 521: 0.253 (n = 1369, err = 258.6)
  
  Number of inner nodes:    2
  Number of terminal nodes: 3
  </code></pre>