Rank test statistics for unbalanced nested designs
2008, Statistical Methodology
https://doi.org/10.1016/J.STAMET.2007.06.001Abstract
We formulate rank statistics for testing hypotheses in unbalanced, and possibly heteroscedastic, twofactor nested designs with independent observations. These include Wald-type statistics based on the theory introduced by Akritas, Arnold and Brunner, as well as a Box-type approximation which is intended to improve the accuracy of approximation to asymptotic distributions. We also present statistics based on a recent theory of weighted F-statistics for ranks. The actual sizes of the statistics at various nominal levels are compared in a simulation study. Our main conclusion is that the Box-adjusted Wald-type statistic is the only statistic that is accurate across all the situations considered and therefore we recommend it for general use.
References (10)
- M.G. Akritas, The rank transform method in some two-factor designs, Journal of the American Statistical Association 85 (1990) 73-78.
- M.G. Akritas, S.F. Arnold, Fully nonparametric hypotheses for factorial designs I: Multivariate repeated measures designs, Journal of the American Statistical Association 89 (1994) 336-343.
- M.G. Akritas, S.F. Arnold, E. Brunner, Nonparametric hypotheses and rank statistics for unbalanced factorial designs, Journal of the American Statistical Association 92 (1997) 258-265.
- M.G. Akritas, A. Stavropoulos, C. Caroni, Asymptotic theory of weighted F-statistics based on ranks (submitted for publication).
- S.F. Arnold, The Theory of Linear Models and Multivariate Analysis, John Wiley, New York, 1981.
- E. Brunner, H. Dette, A. Munk, Box-type approximations in nonparametric factorial designs, Journal of the American Statistical Association 92 (1997) 1494-1502.
- W.J. Conover, R.L. Iman, Rank transformations as a bridge between parametric and nonparametric statistics (with discussion), American Statistician 35 (1981) 124-133.
- S.C. Hora, W.J. Conover, The F statistic in the two-way layout with rank-score transformed data, Journal of the American Statistical Association 79 (1984) 668-673.
- R.L. Iman, S.C. Hora, W.J. Conover, Comparison of asymptotically distribution-free procedures for the analysis of complete blocks, Journal of the American Statistical Association 79 (1984) 674-685.
- G.A. Milliken, D.E. Johnson, Analysis of Messy Data. Vol. I: Designed Experiments, Chapman and Hall/CRC, Boca Raton, 1992.