What is a critical reason for using a larger number of mice in an experiment?

Using a larger number of mice in an experiment significantly enhances the statistical reliability of the results. This is because a larger sample size provides a more accurate representation of the population being studied, allowing for better detection of true effects or differences. With more individuals, the data collected are less influenced by outliers or random variation, which can skew results in smaller samples. Thus, conclusions drawn from the results are more robust and can be generalized to a wider population. A larger sample size also increases the power of statistical tests, making it more likely to detect a significant effect if one exists.

In contrast, minimizing ethical concerns, ensuring all mice develop cancer, or making the experiment easier to conduct do not directly address the importance of statistical reliability in experimental outcomes. While ethical considerations are crucial in research involving animals, they do not inherently justify a larger sample size. Similarly, it is not necessary to ensure that every subject develops a specific condition, nor does increasing the number of subjects inherently simplify experimental procedures.