Correlation in simple terms is when two things are somehow related to each other. Imagine you want to find out if the amount of ice cream eaten affects your mood. If your mood improves after eating more servings, there may be a correlation. This does not mean that ice cream directly makes you happy — there can sometimes be other factors. But there may be a certain connection.
To understand if this correlates in life, statistics are often looked at. But in everyday life, it is usually just an observation. For example, you notice that when you sleep more, you feel better. Here, one can assume that the quality of rest and energy are somehow correlated.
What correlation means in simple terms is a way to understand if two things go together. It is important to remember that even if they correlate, it does not mean that one is definitely the cause of the other. Just observe your life, and you will be able to notice many such connections.
Correlation is a statistical measure that reflects the degree of relationship between two variables. Simply put: does one quantity change along with another, and if so — how strongly and in which direction.
Types of correlation:
-
Positive correlation — when one variable increases, the other also increases (for example, the more time a person studies — the higher the grades);
-
Negative correlation — when one variable increases, the other decreases (for example, the faster the speed — the less time on the road);
-
Zero (no) correlation — changes in one variable do not affect the other.
How is it measured? The Pearson correlation coefficient is often used:
Values range from -1 to +1:
+1 — perfect positive correlation;
0 — no correlation;
–1 — perfect negative correlation.
Important: Correlation ≠ Causation.
If two things change together — it does not mean that one causes the other.
For example, in summer, ice cream sales and the number of drownings increase. They correlate, but one does not cause the other — the common cause here is hot weather.