An EM-Algorithm Based Method to Deal with Rounded Zeros in Compositional Data under Dirichlet Models
May 11, 2011
DOI:
Published in: Proceedings of the 4th International Workshop on Compositional Data Analysis (CODAWORK2011)
Zeros in compositional data are classified into “rounded” zeros and “essential” zeros. The rounded zero corresponds to a small proportion or below detection limit value while the essential zero is an indication of the complete absence of the component in the composition. Several parametric and non-parametric imputation techniques have been proposed to replace rounded zeros and model the essential zeros under logratio model. In this paper, a new method based on EM algorithm is proposed for replacing rounded zeros. The proposed method is illustrated using simulated data.