Oh, and to answer your question more directly, the randomization test permits testing hypotheses using any metric, so scale & shape are definitely testable.
Typically one is interested in means, so on each iteration of the test loop one computes the group/condition means. However, it's simple to instead compute, say, the best fit weibull to each condition and simultaneously test shift, shape, and scale. On Tue, Mar 31, 2009 at 12:18 PM, Mike Lawrence <mike.lawre...@dal.ca> wrote: > Those with more formal statistical backgrounds may provide better > advice, but in my own informal training I've come to wonder why > parametric stats persist in the face of modern computing power. As I > understand it, Fisher developed ANOVA as low-computation method of > approximating the Randomization Test (a.k.a. exhaustive permutation > test). Where computation power has grown exponentially since Fisher's > time, these days it is feasible to compute the full R-Test in many > cases, and for those cases where the full R-Test is not feasible, > non-exhaustive permutation variants usually satisfy. Indeed, it has > been shown (http://brm.psychonomic-journals.org/content/37/3/426.short) > that the R-Test is more powerful than the F-Test in the face of skewed > distributions. > > My advice would thus be to abandon parametrics and simply code a > randomization test variant of the ANOVA you want. > > Mike > > On Tue, Mar 31, 2009 at 10:29 AM, Sarti Maurizio <sart...@irea.cnr.it> wrote: >> Dear R-Helpers, >> >> Parametric statistics are statistics where the population is assumed to fit >> any >> parametrized distributions (most typically the normal distribution). >> My problem is: >> 1) if my polulation is no normal >> 2) if the sample data of all replications and treatments were well fitted >> from >> the Weibull distribution (shape and scale parameters). >> >> Can be The shape and scale parameters compared between treatments by using >> the >> canonical analysis of the variance ANOVA? >> >> Many thanks for your help with these questions. >> >> Maurizio >> >> ______________________________________________ >> 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. >> > > > > -- > Mike Lawrence > Graduate Student > Department of Psychology > Dalhousie University > > Looking to arrange a meeting? Check my public calendar: > http://tinyurl.com/mikes-public-calendar > > ~ Certainty is folly... I think. ~ > -- Mike Lawrence Graduate Student Department of Psychology Dalhousie University Looking to arrange a meeting? Check my public calendar: http://tinyurl.com/mikes-public-calendar ~ Certainty is folly... I think. ~ ______________________________________________ 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.
