What is the difference between a p-value and an effect size in rodent studies, and why are both important?

• A. P-value indicates practical importance; effect size indicates whether the result is due to chance.
• B. P-value indicates whether an observed effect could be due to chance; effect size quantifies the magnitude of the effect.
• C. P-value measures sample size; effect size measures p-value.
• D. P-value and effect size are interchangeable.

Answer: (B)