<p>Taken from the <a href="http://meta.stackexchange.com/questions/16721/how-does-accept-rate-work/16729#16729">Meta.SO Post</a> on accept rates:</p>

<blockquote>
  <p><strong>Which questions do not affect the accept rate?</strong></p>
  
  <p>The following questions are not included in the accept rate
  calculation:</p>

<pre><code>Community Wiki Questions
Closed Questions
Questions with no answers
</code></pre>
</blockquote>

<p>Thanks to <a href="http://meta.superuser.com/users/78429/bckbck">@bckbck</a> for answering it in the comments originally. </p>