The unequal variance t-test is an underused alternative to Student's t-test and the Mann-Whitney U test
The unequal variance t-test is an underused alternative to Student's t-test and the Mann-Whitney U test
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DOI：
10.1093/beheco/ark016
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发表时间：
2006-07-01
影响因子：
2.4
通讯作者：
Ruxton, GD
中科院分区：
文献类型：
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作者：
Ruxton, GD
通常在行为生态学的研究中，以及更广泛的科学中，我们需要在统计学上测试两组样本的中心趋势（平均值或中位数）是否彼此不同。在调查《行为生态学》（第16卷，第1-5期）最近的几期时，我发现，在130篇论文中，有33篇（25%）至少使用了一种这种统计比较。使用三种不同的检验进行比较：Student t检验（67次; 26篇论文）、Mann-Whitney U检验（43次; 21篇论文）和不等方差t检验（9次; 4篇论文）。我在这篇论坛文章中的目的是为了更好地使用最后一个测试。刚才提到的数字表明，这种测试并不常用。在我的调查中，我能够确定简单地描述为“t检验”的检验，并有信心作为学生t检验或不等方差t检验，因为2个样本量的自由度计算对于2个检验是不同的（见下文）。因此，忽略上述不等方差t检验是一个真实的现象，可以用几种（非排他性的）方式来解释：
Often in the study of behavioral ecology, and more widely in science, we require to statistically test whether the central tendencies (mean or median) of 2 groups are different from each other on the basis of samples of the 2 groups. In surveying recent issues of Behavioral Ecology (Volume 16, issues 1–5), I found that, of the 130 papers, 33 (25%) used at least one statistical comparison of this sort. Three different tests were used to make this comparison: Student’s t-test (67 occasions; 26 papers), Mann–Whitney U test (43 occasions; 21 papers), and the t-test for unequal variances (9 occasions; 4 papers). My aim in this forum article is to argue for the greater use of the last of these tests. The numbers just related suggest that this test is not commonly used. In my survey, I was able to identify tests described simply as ‘‘t-tests’’with confidence as either a Student’s t-test or an unequal variance t-test because the calculation of degrees of freedom from the 2 sample sizes is different for the 2 tests (see below). Hence, the neglect of the unequal variance t-test illustrated above is a real phenomenon and can be explained in several (nonexclusive ways) ways: