Robustness of Multiple Comparison Procedures: Treatment versus Control

✍ Scribed by Dr. P. E. Rudolph

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 271 KB
• Volume: 30
• Category: Article
• ISSN: 0323-3847
• DOI: 10.1002/bimj.4710300106

✦ Synopsis

Academy of Agricultural Sciences of the GDR, Research Centre of Animal Production Dummerstorf-Rostock

Computer simulation techniques were used to investigate the Type I and Type I1 error rates of one parametric (Dunnett) and two nonparametric multiple comparison procedures for comparing treatments with a control under nonnormality and variance homogeneity. It was found that Dunnett's procedure is quite robust with respect to violations of the normality assumption. Power comparisons show that for small eample sizm Dunnett's procedure is superior to the nonparametric promdures also in hon-normal cases, but for larger Bample sizes the multiple analogue to Wilcoxon and Kruskal-Wallis rank statistics are superior to Dunnett's procedure in all considered nonnor-ma1 cases. Further inveatigations under nonnormality and variance heterogeneity show robustness properties with respect to the risks of first kind and power comparisons yield similar results as in the equal variance case.