I need some help to produce histograms regarding my data about an algae density collected in 8 sampling sites, 4 times a year, for 5 years.
I would like to analyse them, underlining the differences in density, for each site, both among times and years but I don't know how to do this.
I can create a layer for each considered year but I'm not able to see how to compare with histograms the density among years for each site.
Best Answer
You can try the QGIS plugin to analyse your data using R packages. The link above can give some tips:
http://arc-team-open-research.blogspot.com.br/2013/01/manager-usefull-plugin-for-qgis.html
Or you can export your data to one statistical software and run the analyses there. I'm still recommending R.
http://www.statmethods.net/graphs/density.html