Bewick Viv, Cheek Liz, Ball Jonathan
Senior Lecturer, School of Computing, Mathematical and Information Sciences, University of Brighton, Brighton, UK.
Crit Care. 2004 Feb;8(1):46-53. doi: 10.1186/cc2428. Epub 2003 Dec 30.
This review introduces methods for investigating relationships between two qualitative (categorical) variables. The chi2 test of association is described, together with the modifications needed for small samples. The test for trend, in which at least one of the variables is ordinal, is also outlined. Risk measurement is discussed. The calculation of confidence intervals for proportions and differences between proportions are described. Situations in which samples are matched are considered.
本综述介绍了研究两个定性（分类）变量之间关系的方法。描述了关联性的卡方检验以及小样本所需的修正。还概述了趋势检验，其中至少有一个变量是有序的。讨论了风险测量。描述了比例的置信区间以及比例差异的计算。考虑了样本匹配的情况。
