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.