Simone Vincenzi-2 wrote: > > I have a statistical problem with the comparison of short time-series, > representing densities of fish in different streams. For each stream (6 in > total, here below showed only part of the dataset) I have 8 years of > density > data, as follows: > > > year density stream > > 1 2000 0.51 stream1 > > 2 2001 0.87 stream1 > Are mean densities different among streams from 2000 to > 2007? Is it sufficient and appropriate a test of correlation (using rcorr > of > the library Design, for example) to test if density trends in time are > similar among streams? > >
Have a look at function gls in in package nlme. gls(density~year*stream,....) There are some similar examples in the book coming with nlme (chapter 5.4) Dieter -- View this message in context: http://n4.nabble.com/Comparing-means-and-trends-in-short-time-series-tp1474688p1474750.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
