title: A new powerful nonparametric rank test for ordered alternative problem.
abstract: We propose a new nonparametric test for ordered alternative problem based on the rank difference between two observations from different groups. These groups are assumed to be independent from each other. The exact mean and variance of the test statistic under the null distribution are derived, and its asymptotic distribution is proven to be normal. Furthermore, an extensive power comparison between the new test and other commonly used tests shows that the new test is generally more powerful than others under various conditions, including the same type of distribution, and mixed distributions. A real example from an anti-hypertensive drug trial is provided to illustrate the application of the tests. The new test is therefore recommended for use in practice due to easy calculation and substantial power gain.
authors.affiliation: Epidemiology and Biostatistics Program, Department of Environmental and Occupational Health, School of Community Health Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, United States of America.
authors.forename: Guogen
authors.initials: G
authors.lastname: Shan
authors.affiliation: Division of Health Sciences, University of Nevada Las Vegas, Las Vegas, Nevada, United States of America.
authors.forename: Daniel
authors.initials: D
authors.lastname: Young
authors.affiliation: Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia, United States of America.
authors.forename: Le
authors.initials: L
authors.lastname: Kang
mesh_terms: D003627:Data Interpretation, Statistical; D013223:Statistics as Topic / Q000379:methods*; D018709:Statistics, Nonparametric