title: show volume in each node using ctree , plot in R
body: <p>can any one please show me how to add volume in each of the nodes , instead of the final node volume </p>
  
  <pre><code>t &lt;- ctree(is_return ~ a + b + c)    
  plot(t, type="simple")
  </code></pre>
  
  <p>and my tree would look like </p>
  
  <p><img src="https://i.stack.imgur.com/mr6TS.jpg" alt="enter image description here"></p>
  
  <p>how can I modified that plot where it would show N= on every circle nodes , not only the black or the final node. </p>
  
  <p>Thanks</p>