Randomization in the analysis of covariance
协方差分析中的随机化
When examining any linear contrast of adjusted treatment means in the analysis of covariance it is shown that balancing on the covariates is desirable in that it minimizes the model variance of the treatment contrast averaged over the randomization distribution. Approximate balancing, through truncation of the randomization distri bution, is examined empirically. It is shown empirically that robustness of the test statistic can be achieved through truncated randomization.…