A negative correlation is said to exist when as one covariate increases the other covariate decreases. An excellent example of a negative correlation would be number of hours spent socialising by a group of students and their eventual examination mark. Going out too much seriously jeopardises your examination success.
a relationship between two variables wherein increases in the value of one variable are associated with decreases in the value of the other variable
a correlation in which large values of one variable are associated with small values of the other; the correlation coefficient is between 0 and -1