What does a null hypothesis predict?

The null hypothesis serves as a foundational concept in statistical testing and research methodology. It predicts that there is no relationship or difference between the variables being studied. When researchers formulate a null hypothesis, they are positing that any observed effects or correlations in their data are due to chance rather than a true underlying relationship.

This hypothesis is critical because it provides a baseline against which the effects of the independent variable can be compared. Researchers aim to either reject or fail to reject the null hypothesis through their analysis. If the null hypothesis is rejected, it implies that there is enough evidence to suggest a significant relationship or difference exists among the variables being assessed.

While the other options propose different scenarios regarding relationships or differences in variables, they do not align with the essence of what a null hypothesis articulates. A null hypothesis focuses explicitly on the absence of any relationship or difference, which is why the prediction of "no relationship between two or more study variables" is the correct interpretation of its purpose in research.