What is the name of the statistical test that was used to find the power from the following information?

The results from the two replicates were within 2% of each other. Further, n=2 produced a variance reduction of 40% and a power of 0.70. Therefore, there were not a lot of variances. I have sufficient resolution to meet my signal-to-noise ratio (which is sufficiently large). Therefore, doing an extra replicate doesn't provide me any difference in meeting my scientific objectives.