What does a null hypothesis signify?

A null hypothesis signifies a foundational concept in statistical testing, specifically stating that there is no significant effect or difference between groups or variables being studied. This assertion serves as a starting point for statistical analysis, establishing a baseline against which alternative hypotheses, which propose that a significant effect or difference does exist, can be tested.

By positing that any observed effect is due to random chance rather than a true effect, researchers can use data to determine whether to reject or fail to reject this null hypothesis. This process is key to making informed decisions based on empirical evidence, as it allows for the evaluation of causal relationships and the testing of assumptions. The null hypothesis plays a critical role in hypothesis testing, contributing to the rigor and validity of statistical conclusions.