title: What are the options for na.action in boxplot?
body: <p>Two questions related to <code>boxplot</code>: </p>
  
  <ol>
  <li>What are the options for <code>na.action</code>?  The documentation doesn't list them.</li>
  <li>How would I go about answering these types of question in the future?</li>
  </ol>