Thanks Bob This is great, The correlation does jump out when I plot it- I am just looking for a quantified way of testing what I see. If there is a more appropriate test I'd be happy to learn.
Many thanks Tania Bird MSc *"There is a sufficiency in the world for man's need but not for man's greed" ~ Mahatma Gandhi* https://www.linkedin.com/in/taniabird https://taniabird.webs.com On 26 July 2017 at 12:51, Bob O'Hara <boh...@senckenberg.de> wrote: > You can pass the columns to ccf() directly: > > df <- data.frame(x=rnorm(6), y=rnorm(6)) > ccf(df$x, df$y) > print(ccf(df$x, df$y)) > > You should probably also check the time series task view: < > https://cran.r-project.org/web/views/TimeSeries.html>, in particular the > zoo package, to see what can be done with irregular time series. > > But with 6 data points I'd be surprised if you have the power to detect > anything that doesn't jump out when you simply plot the data. > > Bob > > > On 26/07/17 11:07, Tania Bird wrote: > >> I have three data sets of abundances through time for plants, insects and >> reptiles. >> There are 6 samples over a ten year period (all taxa sampled at the same >> time). >> I recognise this is a small data set for time series. >> >> I would like to correlate the time series to see if >> a) increases in abundance of one taxon are correlated to another, and >> b) to see if the correlation between plants:insects is greater than >> plants:reptiles. >> >> I thought to use the cross-correlation function in R >> e.g. ccf(insects, reptiles) >> >> Currently the data is in one dataframe with time as one column and >> abundance of each taxa is the next three columns. >> >> How do I convert the data to a time.series format as given in the R >> example? >> >> How can I compare the two ccf outputs? >> >> Thanks >> >> Tania >> >> >> Tania Bird MSc >> *"There is a sufficiency in the world for man's need but not for man's >> greed" ~ Mahatma Gandhi* >> >> [[alternative HTML version deleted]] >> >> _______________________________________________ >> R-sig-ecology mailing list >> R-sig-ecology@r-project.org >> https://stat.ethz.ch/mailman/listinfo/r-sig-ecology >> >> > > -- > Bob O'Hara > NOTE: this email will die at some point, so please update you records to > bob.oh...@ntnu.no > > Institutt for matematiske fag > NTNU > 7491 Trondheim > Norway > > Mobile: +49 1515 888 5440 > Journal of Negative Results - EEB: www.jnr-eeb.org > > _______________________________________________ > R-sig-ecology mailing list > R-sig-ecology@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-ecology > [[alternative HTML version deleted]] _______________________________________________ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
