On Mon, May 9, 2011 at 10:20 AM, Nicole Gross-Camp <n.gross-c...@uea.ac.uk> wrote: > I have what I hope is a simple question - is it possible to do time series > analysis on a small data set specifically only four data points? > > > > I have collected human threat data (mean number of threats per kilometre > walked/ survey) every 3 months in eight different sites (four with an > experimental element and four control sites). I am trying to determine the > best way to determine if there is a trend in the data though from what I've > seen of TSA, our data set is too small. I did a simple paired t-test on the > first and average of following three surveys that shows no significant > difference but it of course ignores the detail of the latter three surveys. > > > > I am not sure how to organize the data for importation into R. I've looked > at Crawley and one of Zuur publications but the TS data they work with is > much longer term and not over several (independent) sites. > > > > Any advice, help, or direction is much appreciated! >
This i panel data where you have 8 time series, not one time series, right? You could try a gls model with an AR1 correlation error structure for each of the 8 series. See the analysis of the Owl data set in Zuur. -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.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.
