Areal compositions by abundance of vegetation and animals for 50 plots in each of regions A and B.
data(AnimalVegetation)
In a regional ecology study, plots of land of equal area were inspected and the parts of each plot which were thick or thin in vegetation and dense or sparse in animals were identified. From this field work the areal proportions of each plot were calculated for the four mutually exclusive and exhaustive categories: thick-dense, thick-sparse, thin-dense, thin-sparse. These sets of proportions are recorded for 50 plots from each of two different regions A and B.
All rows sum to 1, except for some rounding errors.
Aitchison: The Statistical Analysis of Compositional Data, 1986, Data 25, pp22.