You might want to start by re-expressing the "amounts" variables to total amount * (relative fish 1, relative fish 2, invertebrates) and then using the Isometric Log-ratio transformation to convert the compositional part to orthonormal coordinates. https://stats.stackexchange.com/questions/259208/how-to-perform-isometric-log-ratio-transformation may help.
I can't help wondering whether viewing the diet in terms of the nutrients offered by the different components might yield more insight. On Sat, 18 Apr 2020 at 11:00, Tristan Kosciuch <tristan.kosci...@mail.mcgill.ca> wrote: > > Hello, > > I am modelling the diet of Nile perch through time. I have 3 diet classes as > my response variables; fish 1, fish 2, and invertebrates. > > The response variables are correlated, declines in invert consumption ~ > increase in fish consumption. Any advice on how to handle this would be > appreciated. I would like to use GAMs as my time series shows fluctuations > that could only be fit by high order polynomials if I were to use a linear > model, but open to suggestions. > > Thank you for your time. > > P.s. I will be comparing the fit of the time series GAM with a model based > on other predictors, with a training and validation split for my data. > > > > --- > > Tristan Kosciuch > > Stewart Biology Building, McGill University > > 1205 Dr Penfield Ave, Montreal QC H3A 1B1 > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
