In clinical research, comparisons of the results from experimental and control groups are often encountered. The two-sample t-test (also called independent samples t-test) and the paired t-test are probably the most widely used tests in statistics for the comparison of mean values between two samples. However, confusion exists with regard to the use of the two test methods, resulting in their inappropriate use. In this paper, we discuss the differences and similarities between these two t-tests. Three examples are used to illustrate the calculation procedures of the two-sample t-test and paired t-test.
临床研究中经常遇到比较实验组和对照组之 间的结果。双样本t 检验（又称为独立样本t 检验） 和配对t 检验可能是运用于比较两个样本之间均值 的最广泛的统计方法。然而，这两种方法的运用会 产生混淆，从而导致使用不当。本文中，我们讨论 了这两种t 检验之间的异同性，并运用三个范例来 阐述双样本t 检验和配对t 检验的计算过程。.
Keywords: independent t-test; matched paired data; paired t-test; pre- and post-treatment.