ESTIMATING AND TESTING WITH THE BHATTACHARYA PLOT

Mixtures of subpopulations of biological particles are appropriately described by finite mixture densities. Often, samples drawn from such populations are condensed in the form of histograms. In the exploratory phase of a parametrical data analysis, one wishes to obtain first estimates for the parameters of such mixtures. A parameter of special significance is the number of subpopulations. For the case of univariate normal mixtures, an explanatory graphical device called Bhattacharya Plot is presented. It allows one to obtain the required first estimates and provides assistance in the test of the normality of the mixture. The degree of overlapping in the histogram must not be too severe.