Fig. 3.

Impact of sample size and the minimally detectable effect size on power.

The graph shows the statistical power for a given sample size (per group) in different scenarios of minimally detectable effect sizes ranging from 1.20 to 2. Commonly, a power of 80% is used in power calculation. Therefore, the sample size (X-axis) at which the dashed horizontal grey line crosses the line with the desired effect size is the sample size needed to achieve enough power to detect that effect size. Effect sizes are indicated as fold-change (FC). Smaller effect sizes require a larger sample size.