Graphical representation of two mixed-Weibull distributions

A variety of shapes of two-Weibull mixtures on Weibull probability paper are explored and classified into six types of Cdf curves (A-F). Types B-D represent Cdf´s composed of two well-mixed subpopulations. Type F represents the Cdf composed of two very well-separated subpopulations. Types A and E are in between types B-D and type F. The Kao-Cran graphical parameter estimation method cannot be applied to type A-C, E, and F curves. It is recommended that it not be applied to the type D curve. The theoretical basis is developed for the Jensen-Petersen graphical method for mixtures with well-separated subpopulations, viz, the type F curve. For type A and E curves, the method can be applied. However, for type B-D curves, there is no theoretical basis for the method