THE COMPARISON OF PERCENTAGES IN MATCHED SAMPLES
THE COMPARISON OF PERCENTAGES IN MATCHED SAMPLES
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DOI：
10.1093/biomet/37.3-4.256
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发表时间：
1950-01-01
期刊：
影响因子：
2.7
通讯作者：
COCHRAN, WG
中科院分区：
文献类型：
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作者：
COCHRAN, WG
X2检验长期以来一直用于检验两个或多个独立样本中比率或百分比之间差异的显著性。有时候，一个样本中的每一个成员都会与其他样本中的相应成员进行配对，以期在百分比之间进行更准确的比较。配对可能基于成员的特征，或者基于这样一个事实，即一个群体中的合作伙伴接受一些测试，这些测试对该群体的所有成员都是相同的，但在不同的群体中有所不同。由于配对可能会在不同样本的结果之间引入相关性，因此它使普通的X2测试无效，如果配对有效，则该测试给出的显著结果太少。对于有两个样本的情况，很容易构造适当的检验。McNemar（1949）给出了一个例子，他提出了这个检验。在他的数据中，205名士兵被问及他们是否认为对日战争将持续一年以上或不到一年。在一次关于抗日战争的困难的演讲之后，他们被问到了同样的问题。匹配的发生是因为每个样本包含完全相同的士兵。
The x2 test has long been used to test the significance of differences between ratios or per-centages in two or more independent samples. It sometimes happens that each member of a sample is matched with a corresponding member in every other sample, in the hope of securing a more accurate comparison among the percentages. The matching may be based either on the characteristics of the members, or on the fact that the partners in a group are subjected to some test that is the same for all members of the group but varies from one group to another.Since the matching may introduce correlation between the results in different samples, it invalidates the ordinary X2 test, which gives too few significant results if the matching is effective. For the case where there are two samples, an appropriate test is easily constructed. An example has been given by McNemar (1949), who presents this test. In his data, 205 soldiers were asked whether they thought that the war against Japan would last more or less than a year. They were subsequently asked the same question after a lecture on the difficulties of the war against Japan. Matching occurs because each sample contains exactly the same soldiers.