<p>This topic is motivated from this question: <a href="https://stats.stackexchange.com/questions/90902/why-is-leave-one-out-cross-validation-loocv-variance-about-the-mean-estimate-f">Why is leave-one-out cross-validation (LOOCV) variance about the mean estimate for error high?</a> </p>

<p>The top answer starts with </p>

<blockquote>
  <p>Oct 2015. My original answer here was irrelevant, as pointed out in
  the comments below and in a couple of downvotes. I replace it with a
  new answer now (but save my original answer below).</p>
  
  <p>This is a complicated topic, and I must admit that I don't have a full
  understanding of it.</p>
</blockquote>

<p>This question has 11 up-votes, and it is arguably not a good answer. The user himself is saying that the original answer was irrelevant and that he 
<em>"does not have a full understanding of it"</em>. </p>

<p>I think the problem has to do with the question being very popular, or the problem being a difficult one. In fact, it has been asked several of times, see e.g. <a href="https://stats.stackexchange.com/questions/61783/variance-and-bias-in-cross-validation-why-does-leave-one-out-cv-have-higher-var?noredirect=1&amp;lq=1">this</a>, <a href="https://stats.stackexchange.com/questions/61546/optimal-number-of-folds-in-k-fold-cross-validation-is-leave-one-out-cv-always?noredirect=1&amp;lq=1">this</a> and <a href="https://stats.stackexchange.com/questions/27730/choice-of-k-in-k-fold-cross-validation?noredirect=1&amp;lq=1">this</a>. </p>

<p>I am myself a newcomer, yet I still think answers should be up-voted by veterans, to avoid misleading answers. Or a mechanism for too popular <strong>questions' answers</strong> to be <em>up-vote protected</em>.</p>

<hr>

<p>This post was to warn about a problem I see: misleading up-voted answers, answers that might be up-voted by beginners because they like it or empathize with the answerer saying "This is a complicated topic, and I must admit that I don't have a full understanding of it", or because they see an <em>easy</em> to understand answer, or whatever reason. And I think the problem comes from the <strong>original question</strong> being a hot topic. </p>

<p>Disclaimer: I do not think that the answer provided should be deleted, I just find misleading that it has that amount of up-votes when, in my opinion, does not answer the question, which is exactly </p>

<blockquote>
  <p><em>"Is there a mathematical formula, visual, or intuitive way to understand why that average has a higher variance compared with the
  k-fold cross validation?"</em></p>
</blockquote>
