An extensive power evaluation of a novel two-sample density-based empirical likelihood ratio test for paired data with an application to a treatment study of attention-deficit/hyperactivity disorder and severe mood dysregulation

Abstract

In many case-control studies, it is common to utilize paired data when treatments are being evaluated. In this article, we propose and examine an efficient distribution-free test to compare two independent samples, where each is based on paired observations. We extend and modify the density-based empirical likelihood ratio test presented by Gurevich and Vexler [7] to formulate an appropriate parametric likelihood ratio test statistic corresponding to the hypothesis of our interest and then to approximate the test statistic nonparametrically. We conduct an extensive Monte Carlo study to evaluate the proposed test. The results of the performed simulation study demonstrate the robustness of the proposed test with respect to values of test parameters. Furthermore, an extensive power analysis via Monte Carlo simulations confirms that the proposed method outperforms the classical and general procedures in most cases related to a wide class of alternatives. An application to a real paired data study illustrates that the proposed test can be efficiently implemented in practice.

Keywords:

• empirical likelihood
• likelihood ratio
• nonparametric test
• paired data
• two-sample t-test
• two-sample tests
• Wilcoxon's test

Acknowledgements

This research is supported by the NIH grant 1R03DE020851 – 01A1 (the National Institute of Dental and Craniofacial Research). The authors are very grateful to the Editor and the reviewers for their comments and suggestions that have greatly helped us improve the manuscript.