Covariance

Covariance (Cov) is a measure of the linear relationship between two variables. A positive value indicates a direct or increasing linear relationship, and a negative value indicates a decreasing linear relationship.

The sample correlation coefficient will give us a standardized measure of the linear relationship between two variables. It is generally a more useful measure, as it provides both the direction and the strength of relationship. The covariance and corresponding correlation coefficient have same sign (both are positive o both are negative).