Sand, silt and clay compositions of 39 sediment samples of different water depth in an Arctic lake.
ArcticLake$depth: water depth (in meters).
ArcticLake$x: compositions of three covariates: sand, silt, and clay.
Aitchison: CODA microcomputer statistical package, 1986, the file name ARCTIC.DAT, here included under the GNU Public Library Licence Version 2 or newer.
Sand, silt and clay compositions of 39 sediment samples at different water depth (in meters) in an Arctic lake. The additional feature is a concomitant variable or covariate, water depth, which may account for some of the variation in the compositions. In statistical terminology, we have a multivariate regression problem with sediment composition as predictors and water depth as a response. All row percentage sums to 100, except for rounding errors.
Courtesy of J. Aitchison
Aitchison: The Statistical Analysis of Compositional Data, 1986, Data 5, pp5.