An EM-Algorithm Based Method to Deal with Rounded Zeros in Compositional Data under Dirichlet Models

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