In probability theory and statistics, to call two real-valued random variablesX and Yuncorrelated means that their correlation is zero, or, equivalently, their covariance is zero. If X and Y are independent then they are uncorrelated. It is not true, however, that that if they are uncorrelated, they must be independent. Moreover, uncorrelatedness is a relation between only two random variables, whereas independence can be a relationship between more than two.
