What is the defining characteristic of a directional hypothesis?

A directional hypothesis is characterized by the researcher not only predicting that a relationship exists between variables but also specifying the direction of that relationship. This means that the hypothesis will indicate whether one variable is expected to increase or decrease as the other variable changes. For example, a researcher might posit that an increase in social support leads to a decrease in stress levels, clearly defining both the relationship and its expected direction.

In contrast, a non-directional hypothesis would predict that a relationship exists but does not specify whether it will be positive or negative. The assertion of no relationship pertains more to null hypotheses, which differ greatly from directional hypotheses as they indicate a lack of effect or relationship. Lastly, defining variables qualitatively does not pertain to the prediction of relationships that directional hypotheses focus on, as these hypotheses are more concerned with the quantitative relationships and specific trends between variables.