On 2007-11-23, hadley wickham <[EMAIL PROTECTED]> wrote: >> >> What I need is a reference to the tests implemented in glht, so I can >> decide which one is appropriate for my data. Sequen, Changepoint et >> al. may be common terms in some fields, but not in the references I'm >> working from. > > Have you read the vignette: > http://cran.r-project.org/doc/vignettes/multcomp/multcomp.pdf > ?
Thanks, I have, and I've now reread it, as well as looking at the examples in contrMat. I now understand that Tukey, Dunnett, Sequen et al. are 'convenience' terms, specifying all pair-wise, treatments vs control etc., contrasts. I worked through the numerical example in Dunnett's original paper, and also found a worked example of Tukey-Kramer contrasts, and reproduced the results using glht(LM, linfct = mcp(fac = 'Dunnett')) glht(LM, linfct = mcp(fac = 'Tukey')) I'm still finding the language very difficult. I was taught these methods using SS/MS language. Linear models were mentioned in passing, but the focus was on using (and hopefully understanding) the formulas for filling in the cells in an anova table. Has the linear model focus now replaced the 'traditional' approach I learned? It's been a very frustrating week or two as I try and come to terms with material I thought I already knew, so what I'm wondering is if I'm doomed to repeat this process with every variation on Anova designs I want to analyze in R unless I take the time to study linear models. Today's task, for example, is figuring out how to convert Sokal and Rohlf's two-level nested model II anova into R code, and it's not going well. Thanks, Tyler ______________________________________________ R-help@r-project.org 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.
