In a pebble analysis of glacial tills, the total number of pebbles in each of 92 samples was counted and the pebbles were sorted into four categories red sandstone, gray sandstone, crystalline and miscellaneous. The percentages of these four categories and the total pebble counts are recorded.
data(Glacial)Percentages by weight in 92 samples of pebbles of glacial tills sorted into four categories, red sandstone, gray sandstone, crystalline and miscellaneous. The percentages of these four categories and the total pebbles counts are recorded. The glaciologist is interested in describing the pattern of variability of his data and whether the compositions are in any way related to abundance. All rows sum to 100, except for some rounding errors.
Aitchison: The Statistical Analysis of Compositional Data, 1986, Data 18, pp21.