Linear Correlation Coefficient
Correlation adjusts covariance, so that the relationship between the two variables becomes easy and intuitive to interpret.
Note: -1 <= correlation coefficient <= 1
Correlation coefficient of 1 implies, the entire variability of one variable is explained by the other. they are moving in same direction.
Correlation coefficient of 0 implies, the 2 variables are absolutely independent from each other.
Correlation coefficient of -1 implies, the variables are moving opposite direction to each other. eg: icecream and umbrella sales.
Note: Corrrelation(x,y) = Corrrelation(y,x)
Also Note: CORRELATION DOES NOT IMPLY CAUSATION