Comment by KarlKemp | Hacker News Reader

Comment by KarlKemp | Hacker News Reader

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This is... quite wrong? The dictionary says:

  1. a mutual relationship or connection between two or more things
  2. [Statistics] interdependence of variable quantities.
  3. [Statistics] a quantity measuring the extent of the interdependence of variable quantities.

The most sympathetic to your definition is Wikipedia:

    In statistics, correlation or dependence is any statistical
    relationship, whether causal or not, between two random variables or bivariate
    data. In the broadest sense correlation is any statistical association, though 
    it actually refers to the degree to which a pair of variables are linearly 
    related.

And that's the mathematical formulation. Correlation also has a meaning in everyday speech, and mathematics doesn't have the authority to just adopt terms and then claim people are wrong after they've changed the meaning.

Also correlation very definitely means that knowing <x> tells you something about <y>. And vice versa. Like, for example: its value. Or at least a better idea of it than pure guessing without correlation.

That's s bit unnecessarily pedantic, I think we all understand in which context we are talking about correlation.

Hello, see here for an explanation: https://en.wikipedia.org/wiki/Pearson_correlation_coefficien... It's widely understood that the words "correlation" and "uncorrelated", when used in the context of statistics and not otherwise qualified, are shorthand for this definition in particular. By "otherwise qualified" I mean, for example, saying "Spearman's correlation" (in in the OP's abstract) to specify this one: https://en.wikipedia.org/wiki/Spearman%27s_rank_correlation_...

I think that depends on context. Sometimes, in a technical setting correlation just means dependence as an abstract concept, and this includes non-linear dependence. Similar how in financial circles, volatility doesn't mean standard deviation, but in colloquial settings it does.

That matches my experience too.

Correlation, in general, just means some sort of statistical dependence: knowing x tells you something about y. It's often "operationalized" by computing Pearson's r: it's easy to do and there's lots of associated theory.

However, I would find it absolutely bizarre if someone showed a plot with obvious non-linear dependence and described it as "uncorrelated". In that case, the low r reflects a failure of the measuring tool rather than something being measured.

sorry, scientists always use nomal English words in their region and then it will get meaning in this specific region. It maybe is confused, but the advantage that most people understand English is enough.

I think it's safe to say you're not the intended audience for anything math-related, given that you're going to a dictionary to try to figure things out...

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