What does it mean if a null hypothesis is rejected?

Rejecting the null hypothesis indicates that the evidence gathered from the research data supports a significant effect or difference. In hypothesis testing, the null hypothesis typically states that there is no relationship or no difference between groups or variables. When researchers analyze their data and find sufficient evidence to reject this null hypothesis, it implies that the observed outcome is unlikely to have occurred by chance alone, suggesting that there is indeed a statistically significant relationship or difference.

This notion is rooted in the principle of statistical significance, which helps researchers determine whether their findings can be generalized beyond the sample data. A rejection of the null hypothesis leads to the consideration of the alternative hypothesis, which proposes that there is an effect or relationship that warrants further exploration.