<p>There is no special policy either possible or needed here. Every action is fallible, but within limits correctable! </p>

<ul>
<li><p>Original posters may accept poor or even incorrect answers (and then fade away). It is best not to read too much into question acceptance; always remember that this is just one person's judgment. Sometimes an OP chooses what they wished to hear, or what they understood, or what best fitted their specific needs. Often the pattern of voting indicates other answers that are deeper, fuller, or more interesting to many readers. </p></li>
<li><p>People may post poor or even incorrect answers (and then fade away). </p></li>
</ul>

<p>But people who are competent and confident can and should </p>

<ul>
<li><p>Post good answers. If you have a better answer, post it! </p></li>
<li><p>Explain firmly but politely the limitations or errors of other answers. </p></li>
<li><p>Vote up (and down) accordingly. </p></li>
</ul>

<p>In this specific case, you did what you could, and that's fine.</p>

<p>Note on editing: The tacit policy seems to be that people with sufficient reputation and a reasonably good eye for language, mathematical and statistical formatting should edit <strong>mainly to improve presentation</strong>. Supposed technical errors other than trivial typos should be brought to the attention of posters, with the aim that ideally they make  corrections themselves. Such diffidence is partly for posters' own education (assuming they accept corrections) and partly because editors may be those who are confused or incorrect. </p>
