Because of the difference in the nature of forces to separate toners from their carriers, toner samples involved in characterization (e.g. q/m) and in development or transfer process contain distribution of size and charge density different from each other, and from that in a large supply sump. Simulated characterization samples and process samples are created with their respective selection criteria using the Monte Carlo technique. Statistical analyses on the compositions of toner sizes, charges and charge-to-mass ratios in the simulated samples reveal information important in predicting and understanding the performance of electrophotographic toners.