When we have two numerical sets of data, it's either we have a positive association, negative asscociation or no association.
When we have a negative association, one variable increases as the other variable decreases.
Take a scatter plot as an example. In a scatter plot, if the x variable is increasing as the y variable decreases, we can say that both variables have a negative association.
While if the x variable is increasing as the y variable is increasing, both variables have a positive association.
Therefore, when two numerical sets of data have negative association, the correct statement is:
As one variable increases, the other variable decreases.
ANSWER:
D. As one variable increases, the other variable decreases