Correlation

kor-uh-LAY-shun /ˌkɒrəˈleɪʃən/
nounC1GREIELTSTOEFL
formalacademic

A mutual relationship or connection between two or more things.

In statistics, correlation specifically refers to a statistical relationship between two variables. A positive correlation means they tend to increase or decrease together; a negative correlation means one tends to increase as the other decreases. It does NOT imply causation.

The story behind the word. The word 'correlation' is built from the Latin prefix 'com-' (meaning 'together' or 'with') and 'relatio' (meaning 'a bringing back' or 'a relationship'). So, 'correlation' literally means 'a relationship brought together' or 'a mutual relationship.' This perfectly describes how two things are observed to move or change in connection with each other, emphasizing the 'togetherness' of their relationship.

Word relationships

  • relationship: Relationship is a general term for how things are connected; correlation is a specific statistical relationship, often linear.
  • association: Association is a general connection; correlation is a specific type of statistical association.
  • disconnection: Disconnection implies no link, while correlation implies a link.
  • independence: In statistics, independence means two variables have no statistical relationship, the opposite of correlation.

Commonly confused with

  • Causation: Correlation indicates that two variables move together, but causation means one variable directly influences or produces a change in another. Correlation does not imply causation.

Word family

  • correlate (verb): To have a mutual relationship or connection, in which one thing affects or depends on another.
  • correlated (adjective): Having a mutual relationship or connection.

Collocations

  • strong correlation
  • weak correlation
  • positive correlation
  • negative correlation
  • correlation coefficient

Idioms & expressions

  • correlation does not imply causation

Example sentences

  • "There is a strong positive correlation between hours studied and exam scores." Explaining a statistical finding.
  • "Researchers found a negative correlation between ice cream sales and crime rates, but this doesn't mean one causes the other." Discussing a societal trend.
  • "Identifying correlations between different data points is often the first step in understanding complex systems." Highlighting its importance in data analysis.

Memory hook

Think 'CO-RELATION' as 'CO-existing RELATIONSHIP' between two things. Mutual-relation

When not to use

Do not use 'correlation' to imply that one thing causes another. 'Correlation does not imply causation' is a fundamental principle in statistics.

Fun facts

  • The concept of correlation was significantly developed by Francis Galton in the late 19th century.
  • Spurious correlations are common and often humorous, like the strong correlation between per capita cheese consumption and the number of people who die by becoming tangled in their bedsheets.
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