<p>I agree with many of the points gung makes (and several of his answers to subquestions) but I disagree with the conclusion in relation to the post in question.</p>

<p>I also agree that it has been litigated many times, and the <a href="https://stats.stackexchange.com/help/on-topic">help/on-topic</a> hasn't changed across many iterations of this sort of question... indicating that its contents are as intended (or presumably they would have been changed, or at least a solid call for change would be made).</p>

<p>If we read the <a href="https://stats.stackexchange.com/help/on-topic">help/on-topic</a>, it's on topic if it requires "statistical expertise to understand or answer". I think the indicated question qualifies on that basis. [I don't think every such question does, but there's certainly a subset that do]</p>

<p>Here's a challenge: Let's imagine we find 100 random expert programmers who <em>lack</em> any statistical expertise, and give them full access to the R manuals, language definition, etc. Now get them to answer the original question. How many will successfully do it? (Maybe a couple?) </p>

<p>So now if a somewhat larger proportion of expert statisticians would be able to do it correctly as a result of their statistical background, then there must be something in their statistical expertise that is needed to have a good chance at answering it.</p>

<p>There's room for disagreement about whether <em>expertise is necessary</em> in particular cases (until we actually perform such a test I suppose), and if it's not pretty clear that it is required, a degree of conservatism isn't a bad approach -- but my reading of the question suggests that a considerable degree of statistical expertise is <em>certainly</em> needed to correctly understand what the question is even asking about, and consequently some is required to be confident you have the right answer. (If some of our random expert programmers happened to locate a good solution, would they really know if they had it? Or would they be saying something nearer to "uh, maybe see if this is the sort of thing you want, I don't really know")</p>

<p>In the particular instance here, I strongly doubt that <em>I</em> could easily produce a correct answer without substantial effort, but it wouldn't be a lack of knowledge of R that would be the barrier on this one (I believe my knowledge of R is more than sufficient) -- it would be my lack of substantial familiarity with the statistical problem in question - my own lack of <em>statistical expertise</em>. If I was to try to solve this question, I'd <em>begin</em> by learning more about this particular area of stats, <em>then</em> I'd start searching based on that knowledge. If that doesn't indicate a case where 'statistical expertise is required', I don't know what does.</p>

<p>I think the question at issue here is an example of the sort of question the particular phrase in the help was intended to encompass. Perhaps we should explore (in a new meta question) whether that phrase should be clarified or tightened/rewritten to be more restrictive but as things stand I think it includes the question-that-was-closed as being within the scope of on topic.</p>
