Sample size
nausea and vomiting, pain
The sample size in this study was based on a pilot study. Based on pain severity μ1-μ2 = 1.7, SD = 0.9 and drop rate = 20%, the sample size was estimated 90 patients (45 in each group). Moreover, based on nausea and vomiting severity μ1-μ2 = 4, SD = 3 and drop rate = 15%, the sample size was determined 52 patients (26 in each group). Therefore, regarding the higher sample size required, it was determined as 90 patients (45 in each group).