calculateConc           Target copies estimation
popPCR                  EM Mixture Model fitting of dPCR droplet
                        fluorescence
printSummaryConc        Print result summary of popPCR
printSummaryFit         Print fitted mixture model estimates from
                        popPCR
x_multiPop              dPCR sample w/ >=3 populations
x_onePop                dPCR sample w/ 1 population
x_twoPop                dPCR sample w/ 2 populations
