what does it mean to say two variables are negatively correlated?

a when one variable increases, the other decreases
b when one variable increases, the other also increases
c when one variable decreases, the other also decreases
d both variables change at the same rate

The correct answer is a) when one variable increases, the other decreases.

In a negative correlation, as one variable increases, the other variable tends to decrease. This means that there is an inverse relationship between the two variables. For example, if there is a negative correlation between studying hours and test scores, it means that as the number of studying hours increases, the test scores generally decrease.