Sample Size Using the above stated statistical hypothesis and asymptotic normality of the z statistics in a one-sided test with effect size 0.06, σ value as 0.6, type I error as 0.05 and power set to be 0.9, the estimated sample size is 856. Considering 15% dropout during the follow-up, the required sample is 856/0.85 = 1007. To calculate the effect size, the value of kappa was taken to be 0.35 under alternative hypothesis.