Robert: Do the sampling rates differ for the two locations, or over time but are the same at both locations? It sounds like the former, in which case the data are *not* paired -- e.g. one location may have been sampled monthly, the other weekly. So if this is the case, the OP would first have to create the pairing before proceeding, and I don't know whether this even makes sense for the sorts of measurements he has (to say nothing of the possible loss of information).
If I am correct, then I think either a local consultant (given the OP's admitted ignorance of statistics) or posting on SO, stats.stackexchange.com, is where he should go. If not, then your reply works fine. Cheers, Bert Gunter Genentech Nonclinical Biostatistics (650) 467-7374 "Data is not information. Information is not knowledge. And knowledge is certainly not wisdom." H. Gilbert Welch On Sun, Jan 5, 2014 at 9:30 AM, Robert Baer <rb...@atsu.edu> wrote: > > On 1/4/2014 7:42 PM, Peter Turner wrote: >> >> Hi, I hope the following question is appropriate for the list; reflects >> that I've yet to use R and have limited statistical sensibility. >> >> I've two metal ion concentration data sets, one each for two nearby >> watercourses recorded over the same period (2008 to 2012), for which the >> sampling dates differ across that period. >> >> Would R's cor (stats) function be suitable to obtain a correlation measure >> for the Y data sets? > > Probably if it is paired on years. Start by plotting your data as scatter > plot to check linearity. To read the help: > ?plot > Then read ?cor and note the method argument. By default cor() gives you > Pearson correlation coefficients, but depending on the nature of your data, > non-parametric Spearman or Kendall coefficients might be more appropriate. >> >> Is there a better or more appropriate option? >> >> >> Thanks, Peter >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> 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. > > > ______________________________________________ > 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. ______________________________________________ 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.
