- Sample size calculation has been calculated in the basis of similar Chinese herbal medicine effects in improving AR symptoms (primary outcome) in previous studies. Total sample size is 195 (n=65 per group) using G-Power based on the effect sizes (0.45) of two similar recent studies (Jung, 2011; Yang, 2010). Taking account of about 20% drop-outs, the estimated sample size becomes 234, thus 78 participants in each group.