What does a one-tailed hypothesis allow for in research?

A one-tailed hypothesis is a specific hypothesis that makes a prediction about the direction of the relationship or effect between variables. This means that the researcher believes that one variable will have a greater impact than another in a specified direction. For instance, if a study aims to determine whether a new therapy increases the effectiveness compared to an existing treatment, a one-tailed hypothesis could state that the new therapy will yield better results than the existing one.

This focused approach is beneficial as it allows researchers to concentrate their statistical analysis and power to detect an effect in one specific direction, providing a clearer understanding of how variables interact under the anticipated conditions. Thus, the essence of a one-tailed hypothesis is its directional nature, which distinguishes it from other forms of hypotheses that do not specify a direction.