Determination of sample size is critical, however not easy to do. Sample size defined as the number of observations in a sample should be big enough to have a high likelihood of detecting a true difference between groups. Practical procedure for determining sample size, using G*power and previous dental articles, is shown in this study. Examples involving independent t-test, paired t-test, one-way analysis of variance(ANOVA), and one-way repeated-measures(RM) ANOVA are used. The purpose of this study is to enable researchers with non-statistical backgrounds to use in practice freely available statistical software G*power to determine sample size and power.

翻译：样本量的确定至关重要，然而并非易事。样本量定义为样本中的观测数量，应足够大以确保有较高概率检测到组间真实差异。本研究展示了使用G*power软件及既往牙科文献确定样本量的实用流程。示例涉及独立样本t检验、配对样本t检验、单因素方差分析(ANOVA)及单因素重复测量(RM)方差分析。本研究旨在使非统计学背景的研究者能够实际应用免费统计软件G*power进行样本量与统计功效的确定。