View source for Talk:Correlation

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== Relationship between mean values? ==

The third paragraph of the lead says

:''when used in a technical sense, correlation refers to any of several specific types of relationship between mean values. ''

I’m not sure what this means—e.g., in what sense does the Pearson correlation coefficient measure a relationship between mean values? Can we rewrite this more clearly? [[User:Loraof|Loraof]] ([[User talk:Loraof|talk]]) 19:29, 23 November 2017 (UTC)

:I attempted to improve the language there. Since it's referring to a technical sense I took the liberty of dealing with ambiguity by being slightly more technical. [[User:Glenbarnett|Glenbarnett]] ([[User talk:Glenbarnett|talk]]) 03:45, 19 April 2024 (UTC)

== External video ==

I find the external video "floating link", Lecture 21: Covariance and Correlation, Statistics 110, Harvard University, 49:25, April 29, 2013 slightly unwikipedian. I somewhat dislike external links within a wikipedia article in general (I think they should be relegated to the bottom of the page) but I feel this one crosses some line.
[[Special:Contributions/129.240.43.144|129.240.43.144]] ([[User talk:129.240.43.144|talk]]) 11:31, 28 September 2018 (UTC)
:Agree. Removed per [[Template:External media#When to use]] - readers will ''not'' expect this type of media in the article. (I watched the beginning and it's not like it was compelling viewing.) Thanks for posting this. [[User:Qwfp|Qwfp]] ([[User talk:Qwfp|talk]]) 19:34, 28 September 2018 (UTC)

== Main photo incorrect? ==

Image here: https://en.wikipedia.org/wiki/Correlation_and_dependence#/media/File:Correlation_examples2.svg

The figure second from the left on the bottom row says correlation 0. For all the other figures in that row it makes sense to me, because they are symmetrical and that symmetry is either flat or vertical. However in that example, which is a square tilted upward at an angle, the data are correlated linearly are they not?  <!-- Template:Unsigned IP --><small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/192.195.81.229|192.195.81.229]] ([[User talk:192.195.81.229#top|talk]]) 21:11, 19 March 2019 (UTC)</small> <!--Autosigned by SineBot-->

:I believe the intent is that the square is rotated about its center. The correlation should be zero for any rotation angle.  [[User:Glenbarnett|Glenbarnett]] ([[User talk:Glenbarnett|talk]]) 03:25, 19 April 2024 (UTC)
::The image is slightly flattened (squished vertically relative to its width) which may be distorting the visual impression a bit (without actually changing the correlation). Note the "ring" looks elliptical when it was intended to be circular [[User:Glenbarnett|Glenbarnett]] ([[User talk:Glenbarnett|talk]]) 03:27, 19 April 2024 (UTC)
:::I would add that this article at one point in the past used to say something along the lines that the third row of plots in that image showed dependence with zero correlation. While it doesn't actually say that now, people will continue to gain that impression (because all but one of those plots does that). However the last plot (the four 'circular' point clouds arranged in a square) looks to actually be showing a pair of independent bimodal variables. More specifically I think that in that example each margin is a 50-50 mixture of two Gaussians with different mean but the same standard deviation (albeit the issue is much more general). If within each of the point four clouds the variables were independent, the plot as a whole is. The algebra is easy enough but if algebraic arguments are unconvincing, I was able to replicate the impression of the image by recentering four bivariate standard normals at the corners of a square in the x-y plane and sampling from each with equal probability. For such an example, the empirical bivariate copula is uniform over the unit square. [[User:Glenbarnett|Glenbarnett]] ([[User talk:Glenbarnett|talk]]) 03:58, 19 April 2024 (UTC)

==Article title: discrepancy with the content==
Hello. I wonder why the article is titled 'Correlation and dependence', but the definition states 'correlation or dependence is any statistical relationship ...'. How can this be correctly resolved? --[[User:TadejM|TadejM]] <sup>[[User talk:TadejM|my talk]]</sup> 10:56, 20 July 2021 (UTC)

:I've moved the article to 'Correlation' in accordance with the principle of using one article for one concept. In addition, the article defines both terms as synonyms. --[[User:TadejM|TadejM]] <sup>[[User talk:TadejM|my talk]]</sup> 14:24, 20 July 2021 (UTC)

== Proposed merge of [[Correlation coefficient]] into [[Correlation]] ==
{{Discussion top|result=There is '''consensus against merging [[Correlation coefficient]] to [[Correlation]].''' [[User:Gramix13|Gramix13]] ([[User talk:Gramix13|talk]]) 04:49, 11 June 2025 (UTC)}}
wide overlap [[User:Fgnievinski|fgnievinski]] ([[User talk:Fgnievinski|talk]]) 05:11, 27 February 2025 (UTC)

*'''Oppose''' I am reluctant to merge because there are other correlation coefficient main articles that remain separate such as Pearsons coefficient and rank correlation coefficients. Also correlation is a complex subject. Helps to separate these subtopics instead of combining because otherwise you have to dig through a broad article to find the sub topic. People are not always aware of the differences between discussions on correlation and correlation coefficients. [[User:Ramos1990|&#32;Ramos1990]] ([[User talk:Ramos1990|talk]]) 15:52, 27 February 2025 (UTC)

:'''Strong oppose''' -- this article is very useful as a sort of contentful disambiguation page. I'm here because it was just very useful to me in seeing what kinds of coefficients existed and in locating which one I was looking for. Sure, some correlation coefficients are discussed in the correlation article, but that's <i>why</i> this article doesn't go into much detail. [[User:Mrfoogles|Mrfoogles]] ([[User talk:Mrfoogles|talk]]) 23:44, 10 April 2025 (UTC)
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