ABSTRACT
This chapter estimates the missing units and the number in total of the target population in the two-source situation coping with the independence assumption and heterogeneity in the parameters of capture probabilities. Capture-recapture methods have been widely used in enumerating a population of size N that is difficult to approach. Ordinarily, the methods are well established to estimate wildlife abundance. The contribution is built upon the extension of the Lincoln-Petersen approach by modifying the binary source variable to a non-binary source variable. The chapter assumes that the unknown population size N remains constant during the period of the study, which is referred to as a closed population. To formulate an estimate of population size N, a capture mechanism, for example, trapping, register, diagnostic device, is used to identify units having a characteristic of interest. For a situation of two independent sources, the Lincoln–Petersen estimator is one of the most popular approaches used in capture-recapture studies.
