A Level Psychology OCR Practice Exam 2025 - Free Psychology Practice Questions and Study Guide

A one-tailed hypothesis is characterized by predicting a specific outcome in one direction. This means that the hypothesis asserts that there will be a change or effect in a particular direction rather than simply stating that there will be a change without specifying which way it will go. For instance, if a researcher hypothesizes that a new teaching method will improve test scores, this would be a one-tailed hypothesis because it is predicting a specific directional outcome (i.e., an increase in scores).

In hypothesis testing, this approach is used when the researcher has a strong theoretical or empirical basis for expecting a specific effect in a given direction. Utilizing a one-tailed hypothesis can make it easier to achieve statistical significance, as it focuses on detecting an effect only in one direction, while a two-tailed hypothesis would consider deviations in both directions. This tailored approach is particularly useful in research scenarios where prior evidence strongly supports a directional prediction.