RESEARCH PRODUCT MOMENT CORRELATION COEFFICIENT (R) (CORRELATION COEFFICIENT)

a statistic that is calculated to determine whether a linear relationship exists between two metric variables and it takes values between -1 and +1 (depending on the degree of the relationship). A negative value indicates that the variables move in opposite directions and a positive value indicates that they move in the same direction. A value of 0 indicates that there is no linear relationship (although there may be a non-linear relationship).