Multi response GAM
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.kosciuch at 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 at 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.