Alireza Pakgohar - Departmment of Statistics, Payame Noor University (PNU). Tehran, Iran.
Hossein Mehrannia - Department of Statistics, Behbahan Branch, Islamic Azad University, Behbahan, Iran.

Objective: This review aims to address the critical role of sample size calculation in designing and conducting animal studies related to diabetes and obesity, particularly focusing on experimental comparison methods like ANOVA design. Materials and Methods: We discuss the factors influencing sample size decisions, including type I and type II errors, effect size, and standard deviation. We emphasize the importance of avoiding common pitfalls, such as using rules of thumb or arbitrary choices, and advocate for utilizing established formulas to ensure accurate and reliable sample size determination. Results: This review presents relevant equations for calculating sample size in animal studies with an ANOVA design, providing researchers with a framework for determining the appropriate number of animals needed to achieve robust and ethical research. Conclusion: Accurate sample size calculation is essential for achieving powerful and statistically sound animal studies in diabetes and obesity research. Utilizing established formulas and avoiding arbitrary choices ensures reliable and ethical research practices while minimizing resource waste and maximizing the validity of collected data.

Sample size calculation, Clinical trials, Animal studies, Resource Equation Method, Randomized Controlled Trials Method