Glossary term
Correlation: Meaning and Definition
Reviewed and approved by Dr. Anamika ShrivastavaPublished Last updated
Correlation measures the direction and strength of the linear relationship between two variables. It is positive when they move in the same direction and negative when they move oppositely. It shows association, not cause, and its coefficient always lies between minus one and plus one.
In more detail
Correlation is a number between −1 and +1 that summarises how closely two variables move along a line. Plot the data first, since a curved relationship can give a low value even when the link is strong. Even a high value does not show cause, as a third factor may drive both.
Example
Study hours and marks of six students rise together, with a Pearson coefficient of about 0.96. A price of a good and its quantity demanded usually show negative correlation.
Key points
- −1 ≤ r ≤ +1.
- Correlation is not causation.
- Pearson's r needs a linear relationship.
Common mistake
Concluding that one variable causes the other from a high correlation.
Related terms
Scatter diagramSpearman rank correlation
Where it is explained
This term is explained in Class 11 Statistics Chapter 6: Correlation.