[R] Comparing means and trends in short time-series
dieter.menne at menne-biomed.de
Tue Feb 9 18:33:28 CET 2010
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
> 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
> 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.
There are some similar examples in the book coming with nlme (chapter 5.4)
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