I see, I was afraid for an answer along these lines as my problem now turns into a stat problem (-; Any suggestions on how to analyze such data as given below with weights AND at the same time taking into account that there are repeated measurements?
Best, Ingmar On 17 Dec 2008, at 11:02, Prof Brian Ripley wrote: > Weights are not supported: multistratum aov is designed for > balanced designs and uses projection for which weighting is > inappropriate. > > On Wed, 17 Dec 2008, Ingmar Visser wrote: > >> Dear R-help, >> >> I'm facing a problem with defining a repeated measures anova with >> weighted data. >> Here's the code to reproduce the problem: >> >> # generate some data >> seed=11 >> rtrep <- data.frame(rt=rnorm(100),ti=rep(1:5,20),subj=gl >> (20,5,100),we=runif(100)) >> >> # model with within factor for subjects/repeated measurements, no >> problem >> aov(rt~ti + Error(subj/ti),data=rtrep) >> >> #model with weights and subj as between factor, ie ignoring repeated >> measures, >> #again, no problem >> aov(rt~ti+subj,data=rtrep,weights=we) >> >> #combination of above two: repeated measures AND weights >> aov(rt~ti + Error(subj/ti),data=rtrep,weights=we) >> >> The latter model gives an error (see report below), but only after >> fitting it, ie the error is produced by the >> print and summary methods of the aov objects. >> >> Any guidance is appreciated, best, Ingmar >> >> >> >> >> >> Error produced in printing the fitted aov object: >> >> Call: >> aov(formula = rt ~ ti + Error(subj/ti), data = rtrep, weights = we) >> Note: The results below are on the weighted scale >> >> Grand Mean: 0.112081 >> >> Stratum 1: subj >> >> Terms: >> ti Residuals >> Sum of Squares 2.002826 10.869940 >> Deg. of Freedom 1 18 >> >> Residual standard error: 0.7771007 >> Estimated effects are balanced >> >> Stratum 2: subj:ti >> >> Terms: >> ti Residuals >> Sum of Squares 0.382535 5.540047 >> Deg. of Freedom 1 19 >> >> Residual standard error: 0.5399828 >> Estimated effects are balanced >> >> Stratum 3: Within >> Error in print.aov(xi, ...) : >> dims [product 60] do not match the length of object [100] >> In addition: Warning message: >> In resid * wt^0.5 : >> longer object length is not a multiple of shorter object length >> >> >> Ingmar Visser >> Department of Psychology, University of Amsterdam >> Roetersstraat 15 >> 1018 WB Amsterdam >> The Netherlands >> t: +31-20-5256723 >> >> >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> 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. >> > > -- > Brian D. Ripley, rip...@stats.ox.ac.uk > Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ > University of Oxford, Tel: +44 1865 272861 (self) > 1 South Parks Road, +44 1865 272866 (PA) > Oxford OX1 3TG, UK Fax: +44 1865 272595 Ingmar Visser Department of Psychology, University of Amsterdam Roetersstraat 15 1018 WB Amsterdam The Netherlands t: +31-20-5256723 [[alternative HTML version deleted]] ______________________________________________ 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.
