Douglas - Your question is a bit beyond the scope of this list. It's really at a level appropriate for an advanced graduate student who is already doing a thesis in the area of time series data. Best thing is to see whether you can find some consulting help from a local statistics department.
- tom blackwell - u michigan medical school - ann arbor - On Fri, 22 Aug 2003, Douglas G. Scofield wrote: > Dear R list, > > I have a sequence of weekly observations of number of adults and larvae > in various size classes from a butterfly population living in a > subtropical area with pronounced wet and dry seasons. Wet and dry > seasons are each defined 26 weeks long with fixed start and end dates. > The data span 103 weeks (two seasons each of wet and dry) with some > missing weeks. What I would like to do is compare means of each type of > observation between wet and dry seasons ("Does the number of adults > observed vary by season?"). Not surprisingly there is pronounced > autocorrelation in the data, e.g.: > > dwtest(lm(numadults ~ week)) > > gives > > DW = 0.2727, p-value = < 2.2e-16 > > Note that the effects of this autocorrelation extend across wet-dry and > dry-wet boundaries. > > What would be a way to ask my questions in R? It seems like I'd use > nlme and define a corStruct, but it's unclear to me how I'd do that. > I'm still learning R (and statistics) so detailed answers would be most > appreciated. > > Sincerely, > > Douglas Scofield Department of Biology > [EMAIL PROTECTED] University of Miami > off: (305) 284-3778 P.O. Box 249118 > fax: (305) 284-3039 Coral Gables, FL 33124-0421 > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help > ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help