Well fellow R users, I throw myself on your mercy. Help me, the unworthy, satisfy my employer, the ungrateful. My feeble ramblings follow...
I've searched R-Help, the R Website and done a GOOGLE without success for a one way ANOVA procedure to analyse data that are both non-normal in nature and which exhibit unequal variances and unequal sample sizes across the 4 treatment levels. My particular concern is to be able to discrimintate between the 4 different treatments (as per the Tukey HSD in happier times). To be precise, the data exhibit negative skew and platykurtosis and I was unable to obtain a sensible transformation to normalise them (obviously trying subtracting the value from range maximum plus one in this process). Hence, the usual Welch variance-weighted one way ANOVA needs to be replaced by a nonparametric alternative, Kruskal-Wallis being ruled out for obvious reasons. I have read that, if the treatment with the fewest sample numbers has the smallest variance (true here) the parametric tests are conservative and safe to use, but I would like to do this 'by the book'. TVMIA, Regards, Mike ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html