In hypothesis testing, what is the null hypothesis?

The null hypothesis is fundamentally a statement that there is no effect or no difference in the context of the study being conducted. This serves as a baseline or default position that researchers aim to test. In hypothesis testing, the null hypothesis provides a framework for statistical testing; it implies that any observed variance in data is due to random chance rather than a specific cause or intervention.

Researchers use the null hypothesis as a starting point to determine whether there is enough evidence to reject it in favor of an alternative hypothesis, which posits that there is an effect or difference. Effectively, the null hypothesis is crucial in guiding the methodology and statistical analysis of an experiment, allowing researchers to draw conclusions based on data collected.

Understanding this definition is essential in the field of statistics and healthcare research, as it underpins many of the statistical tests and results that inform clinical decision-making and policy development.