What is Correlation?
In [[statistics]] and [[probability theory]], '''correlation''' is how similar two [[set]]s of [[Information|data]] are.<ref>{{Cite web|date=2021-11-27|title=Correlation and Causation - easily explained! {{!}} Data Basecamp|url=https://databasecamp.de/en/statistics/correlation-and-causation|access-date=2022-07-01|language=en-US}}</ref> This relationship means that if one set of data changes, the other will change as well (at least more commonly than if it were up to pure chance). Correlation does not always mean that one causes the other. In fact, it is very possible that there is a third factor involved. Correlation can have one of two directions: Positive or negative. If it is positive, then the two sets go up together. If it is negative, then one goes up while the other goes down. Lots of different measurements of correlation are used for different situations. For example, on a [[scatter graph]], people draw a [[line of best fit]] to show the direction of the correlation. Correlation can be [[Measurement|measured]] through [[Correlation coefficient|correlation coefficients]]. The most common correlation coefficients are [[Pearson product-moment correlation coefficient|Pearson correlation coefficient]] and [[Spearman's rank correlation coefficient|Spearman's rank correlation]]. Correlation is useful in real life. An example of correlation is the [[Human height|height]] of a [[parent]] and their [[children]].[[File:Positive correltion lobf.JPG|thumb|This scatter graph has positive correlation. You can tell because the ''trend'' is up and right. The red line is a [[line of best fit]].]] == Explaining correlation == ''Strong'' and ''weak'' are words used to describe the strength of correlation. If there is strong correlation, then the points are all close together. If there is weak correlation, then the points are all spread apart. There are ways of making numbers show how strong the correlation is. These measurements are called '''correlation coefficients'''. The best known is the [[Pearson product-moment cor