We use correlation to:
Measure relationships between two variables.
Understand patterns โ like if one variable increases, does the other increase, decrease, or stay the same?
Quantify strength and direction of the relationship using a single number (between -1 and +1).
Compare variables even if they have different units (like height and weight).
Correlation tells you about a relationship but not about cause and effect. (So it doesnโt say one variable caused the other to change.)