<p>I think it's fine to retag (without comment) as long as it is <em>perfectly clear</em> that the problem is homework.  In my experience, around half of the questions the community initially believes to be homework turn out, in fact, not to be so.</p>
<hr />
<h3>Supplement</h3>
<p>Let us bear in mind the description in the <a href="https://stats.stackexchange.com/questions/tagged/homework" class="post-tag" title="show questions tagged &#39;homework&#39;" rel="tag">homework</a> wiki excerpt:</p>
<blockquote>
<p>A routine question from a textbook, course, or test used for a class or self-study.</p>
</blockquote>
<p>Taking a somewhat selfish view--that is, with an attitude of discerning what is best for our <em>community</em>, rather than the original proposer (O.P.)--it seems that &quot;routine&quot; is the operative word.  (Sometimes we can identify the source of a question--but not in a reliable or consistent manner--and it would be presumptuous to suppose we can tell what the purpose of a question is in the mind of its asker!)</p>
<p>&quot;Routine&quot; questions differ from those we are really interested in for several reasons, including</p>
<ul>
<li><p>They tend not to have any specific application.</p>
</li>
<li><p>If any data are included, they are artificial (and often cannot be further explained by the O.P., who knows nothing of their genesis).</p>
</li>
<li><p>They tend not to have any <em>context</em>.</p>
</li>
</ul>
<p>Loading the site with a gallery of such questions potentially diminishes the value of searches and other uses of the site as a reference and ongoing resource.  <strong>Tagging routine questions with <a href="https://stats.stackexchange.com/questions/tagged/homework" class="post-tag" title="show questions tagged &#39;homework&#39;" rel="tag">homework</a> is one way to help future researchers to get great answers to the questions they may face.</strong></p>
<p>These considerations take us away from having to guess why somebody has posed a question and move us toward <em>evaluating the question on its own merits.</em>  I will immediately grant that this does not resolve the issue of what constitutes &quot;homework,&quot; because one reader's &quot;routine&quot; question could be difficult or unusual for another.  I suspect, though, that some questions will be so <em>evidently</em> routine that we should not hesitate to tag them accordingly.  Some of the indications of &quot;routineness&quot; would include</p>
<ul>
<li><p>The question has appeared in almost the same form on a previous thread and has a similar solution that requires straightforward substitutions of numerical values in its statement.  (Example: almost any question calling for using the Normal distribution to convert between z values and p values.)</p>
</li>
<li><p>The question is entirely theoretical, without any applied context.  (Consider whether to migrate such questions to the Math.SE site.)</p>
</li>
<li><p>Solutions are readily available elsewhere on the Web by means of an &quot;obvious&quot; search.  (&quot;Obviousness,&quot; once again, is personal, but I would claim that a search based, say, solely on a question's tags which turns up a solution in the first page would qualify as &quot;obvious.&quot;)</p>
</li>
<li><p>The question is expressed in a test-like format, such as a <a href="https://stats.meta.stackexchange.com/questions/1399/">multiple choice</a> or to fill in a blank.</p>
</li>
<li><p>The language is imperious, as in &quot;Find the answer,...,&quot; &quot;State why,...,&quot; &quot;Prove that,&quot; etc.</p>
</li>
</ul>
<p>In such cases, readers (with sufficient reputation) ought to consider immediately adding the <a href="https://stats.stackexchange.com/questions/tagged/homework" class="post-tag" title="show questions tagged &#39;homework&#39;" rel="tag">homework</a> tag to the question.</p>
