The calculator is for Sidak corrected multiple t-tests. It’s useful for when you have pilot data and have estimates for the mean of the control group and the standard deviations. It allows you to estimate the number of animals required to detect a range of percentage changes from the control group.

Example paragraph:

A power analysis was performed on the primary measure of probe trial performance in the Morris water maze using an alpha of 0.05, and a power of 0.8. Previously acquired data was used for the analysis which had a mean of 24.59 and a standard deviation of 11.21. The clinically relevant therapeutic effect size of a 60% improvement in the task was chosen. This analysis found an n of 14 mice per group is required for the Sidak corrected post-hoc analysis with 6 comparisons. Accounting for the possibility of 10% attrition an n of 16 was chosen for these experiments.

Cohen J. 1988. Statistical Power Analysis for the Behavioral Sciences. 2nd ed.Hillsdale: Lawrence Erlbaum Associates.