is a number in the range -1 to 1 that measures the inter-relationship between two variables. A correlation of 1 implies that each variable is completely determined by the other one, and that both increase or decrease together. A correlation of -1 again implies that they are determined by each other but that one decreases while the other increases. A correlation of 0 implies that there is no relationship between the variables.
Updated on December 4, 2017