What does the confidence level represent in an animal study?

What does the confidence level represent in an animal study?

• A. The probability that observed differences are due to the experimental treatment.
• B. The sample size available for the study.
• C. The p-value associated with the results.
• D. The standard deviation of measurements.

Answer: (A)

Confidence level is about how reliable an interval estimate will be when you repeat the study many times. If you report a 95% confidence interval for the treatment effect in an animal study, it means that, if you could repeat the same experiment over and over and compute a new interval each time, about 95% of those intervals would contain the true effect size. It reflects the long-run frequency of correct intervals, not the probability that the observed difference in this single study is due to the treatment. The p-value and significance relate to how surprising the data would be if there were no real treatment effect, which is a different concept from what the confidence level conveys. In practice, a 95% confidence level gives you a sense of precision and reliability of your estimate across repeated experiments.

Confidence level is about how reliable an interval estimate will be when you repeat the study many times. If you report a 95% confidence interval for the treatment effect in an animal study, it means that, if you could repeat the same experiment over and over and compute a new interval each time, about 95% of those intervals would contain the true effect size. It reflects the long-run frequency of correct intervals, not the probability that the observed difference in this single study is due to the treatment. The p-value and significance relate to how surprising the data would be if there were no real treatment effect, which is a different concept from what the confidence level conveys. In practice, a 95% confidence level gives you a sense of precision and reliability of your estimate across repeated experiments.