<p>When I suspect a question may be off-topic for Cross Validated, I often leave a comment like this:  </p>

<blockquote>
  <p>Welcome to the site, @user31264.  This question seems to be only about
  <code>topic ______</code>. As such it would be off-topic for CV (see our help
  page).  If you have a substantive question about statistics, please
  edit to clarify; if not, this Q may have to be be closed.</p>
</blockquote>

<p>However, "statistics" in this context is shorthand for <em>statistics, machine learning, or data visualization</em>, which is our mandate.  In other words, questions about machine learning are fully on-topic here.  Note that we have a <a href="https://stats.stackexchange.com/questions/tagged/machine-learning" class="post-tag" title="show questions tagged &#39;machine-learning&#39;" rel="tag">machine-learning</a> tag, which is <a href="https://stats.stackexchange.com/tags">our fourth most commonly-used tag</a>, appended to 1469 threads (as of today).  For a full list of the topics that are appropriate for Cross Validated, see <a href="https://stats.stackexchange.com/help/on-topic">What topics can I ask about here?</a> in our help center.  </p>
