Detailed Explanation
The p-value serves as a measure of statistical evidence against the null hypothesis, indicating how likely the observed results would be if there were truly no treatment effect. A small p-value suggests that the observed data are unlikely under the null hypothesis, providing evidence in favor of a treatment effect. By convention, p-values below 0.05 are typically considered statistically significant, though this threshold is arbitrary and should be interpreted in context with effect sizes, confidence intervals, and clinical relevance.