Correlation Definition

Correlation – a statistical association of two or more random values (or random values with some proper accuracy). At the same time, a change in one or more of these quantities results in a systematic change in another or other quantities. The relationship between two random variables is measured by a correlation coefficient, mathematically speaking.

Correlation can be positive or negative, including no statistical relation in a situation, for example, for the independently occurring random variables.

The presence of correlation does not have to mean a causal relationship between the variables. One of the variables can be partly or fully the cause of the other, or maybe both these variables are the result of one or more other causes (in this case, we speak of correlation given by other features).