In a scatter plot, the directions of the relationship typically refer to how the variables relate to each other. The common terms used to describe the direction of relationships are:
- Positive: As one variable increases, the other variable also increases.
- Negative: As one variable increases, the other variable decreases.
The terms vertical and horizontal, however, do not describe the direction of a relationship in the context of how two variables relate to each other in a scatter plot. Instead, they describe the orientation of the axes.
Therefore, the correct answer is vertical.