Shirley E
Toxicology. 1977 Aug;8(1):13-22. doi: 10.1016/0300-483x(77)90019-1.
The increase in precision that can be obtained when the bodyweights of animals at the start of an experiment are used as covariate in the analysis of organ weights is demonstrated. Theoretical reasons are given why the analysis of relative organ weights does not eliminate the indirect effect of treatment on organ weight via its effect on bodyweight. An alternative method, that of analysis or organ weights using the current bodyweight as a covariate, is described. Results from these two methods of analysis carried out on simulated experimental data are presented. Analysis of covariance is demonstrated to be superior to analysis of relative organ weights.
研究表明，在对器官重量进行分析时，将实验开始时动物的体重用作协变量，可以提高分析的精度。文中给出了理论依据，解释了为何相对器官重量分析并不能消除治疗通过对体重的影响而对器官重量产生的间接作用。文中还描述了另一种方法，即使用当前体重作为协变量来分析器官重量。本文展示了对模拟实验数据采用这两种分析方法所得出的结果。结果表明，协方差分析优于相对器官重量分析。
