Zusammenfassung: | |
Background: In many research areas it is necessary to find differences between treatment groups with several variables. For example, studies of microarray data seek to find a significant difference in location parameters from zero or one for ratios thereof for each variable. However, in some studies a significant deviation of the difference in locations from zero (or 1 in terms of the ratio) is biologically meaningless. A relevant difference or ratio is sought in such cases. Results: This article addresses the use of relevance-shifted tests on ratios for a multivariate parallel two-sample group design. Two empirical procedures are proposed which embed the relevance-shifted test on ratios. As both procedures test a hypothesis for each variable, the resulting multiple testing problem has to be considered. Hence, the procedures include a multiplicity correction. Both procedures are extensions of available procedures for point null hypotheses achieving exact control of the familywise error rate. Whereas the shift of the null hypothesis alone would give straight-forward solutions, the problems that are the reason for the empirical considerations discussed here arise by the fact that the shift is considered in both directions and the whole parameter space in between these two limits has to be accepted as null hypothesis. Conclusion: The first algorithm to be discussed uses a permutation algorithm, and is appropriate for designs with a moderately large number of observations. However, many experiments have limited sample sizes. Then the second procedure might be more appropriate, where multiplicity is corrected according to a concept of data-driven order of hypotheses.
|
|
Lizenzbestimmungen: | CC BY 2.0 Unported - https://creativecommons.org/licenses/by/2.0/ |
Publikationstyp: | Article |
Publikationsstatus: | publishedVersion |
Erstveröffentlichung: | 2008 |
Schlagwörter (englisch): | Familywise error rate, Location parameters, Multiple testing problems, Multivariate data, Parameter spaces, Second procedures, Several variables, Small Sample Size, Algorithms, Statistical tests, analytical error, article, data analysis, mathematical analysis, mathematical computing, medical research, methodology, microarray analysis, multivariate analysis, nonparametric test, null hypothesis, rank sum test, sample size, simulation, statistical significance, algorithm, biological model, computer simulation, DNA microarray, gene expression profiling, sample size, signal processing, statistical analysis, statistical model, Algorithms, Computer Simulation, Data Interpretation, Statistical, Gene Expression Profiling, Models, Biological, Models, Statistical, Multivariate Analysis, Oligonucleotide Array Sequence Analysis, Sample Size, Signal Processing, Computer-Assisted |
Fachliche Zuordnung (DDC): | 500 | Naturwissenschaften, 570 | Biowissenschaften, Biologie |
Anzeige der Dokumente mit ähnlichem Titel, Autor, Urheber und Thema.