What does the null hypothesis (H0) represent?

The null hypothesis (H0) is fundamental in statistical hypothesis testing, representing a baseline assumption that there is no effect or no difference between groups or conditions. It serves as a starting point for statistical analysis, allowing researchers to determine whether any observed effects in a study are likely due to chance or if they can be attributed to a significant phenomenon.

When researchers conduct a hypothesis test, they collect data and analyze it to see if there is enough evidence to reject the null hypothesis in favor of an alternative hypothesis (which suggests that there is an effect or a difference). By framing the null hypothesis as a statement of no effect or difference, researchers can apply statistical methods to evaluate the likelihood of observing their data if the null hypothesis were true.

In essence, option C accurately captures the essence of the null hypothesis, enabling researchers to assess the validity of their hypotheses in a systematic and scientifically rigorous manner.