As every first week of July since 2012, a 5-day course on compositional data analysis will be imparted at the University of Girona (UdG) by members of the Research Group on Compositional Data Analysis.
Compositional data are vectors whose components show the relative importance of some parts of a whole. Typical examples are data presented in percentages, ppm, ppb, or the like. Aitchison introduced the logratio approach to analyse compositional data back in the eighties. Since then, progress has been done in understanding the special geometry of their sample space, the simplex.
This CoDaCourse provides an introduction to theoretical and practical aspects of the statistical analysis of compositional data, as well as an informal discussion forum on more advances topics. In the theoretical sessions, the current state of the art in this field will be presented. In the practical sessions, CoDa techniques are applied using the available software CoDaPack and some R packages. An open discussion session is also planned. We encourage you to bring your own data!!!
The following topics will be covered:
• Hypothesis underlying the statistical analysis (sample space, scale).
• The Aitchison geometry on the simplex.
• Coordinate representation; distributions on the simplex.
• Exploratory analysis (centering, variation array, biplot, balances-dendrogram).
• Irregular data: zero values, outliers and missing data.
• Introduction to multivariate analysis: regression, manova, cluster and discriminant.