Confidence level -95%, Power - 80%, Coefficient of variation = 80% Formula for sample size calculation: n = (Zα+Zβ)2 * (σ12 + σ22)) / (m1-m2)2, where Zα is the value of normal distribution corresponding to desired confidence level, Zβ is the value of the Normal distribution corresponding to desired power, σ1 and σ2 are the standard deviation of the two groups. With these assumptions the sample size per group works out as 50.