What is the conventional p-value threshold for statistical significance in biomedical research?

• A. 0.05
• B. 0.5
• C. 0.15
• D. 0.01

Answer: (A)

Statistical significance is typically declared when the p-value is 0.05 or smaller. The p-value is the probability of obtaining results as extreme as what was observed, assuming the null hypothesis is true. Using 0.05 as the standard arose from historical convention, providing a practical balance between limiting false positives (Type I error) and maintaining reasonable study power. It’s important to remember that a p-value does not tell you the probability that the null hypothesis is true or the real-world importance of the finding. In biomedical research, this threshold is common, but interpretation should also consider effect size, confidence intervals, study design, and adjustments for multiple comparisons.