Dear R-help I have two separate experiments, one a repeated-measures design, the other a split-plot. In a standard ANOVA I have usually undertaken a multiple-comparison test on a significant factor with e.g TukeyHSD, but as I understand it such a test is inappropriate for repeated measures or split-plot designs.
Is it therefore sensible to use Helmert contrasts for either of these designs? Whilst not providing all the pairwise comparisons of TukeyHSD, presumably the P-statistic for each Helmert contrast will indicate clearly whether that contrast is significant and should be retained in the model. (This seems to come with the disadvantage that the parameter values are harder to interpret than with Treatment contrasts.) In the repeated-measures design the factor in question has three levels, whilst in the split-plot design it has four. Many thanks in advance Roy ---------------------------------------------------------------------------- ------- Roy Sanderson Institute for Research on Environment and Sustainability Devonshire Building University of Newcastle Newcastle upon Tyne NE1 7RU United Kingdom Tel: +44 191 246 4835 Fax: +44 191 246 4999 http://www.ncl.ac.uk/environment/ [EMAIL PROTECTED] ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
