Sarmiento Rondón, William B.

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    Estimación de la proporción de una subpoblación oculta a través de muestreo por “bola de nieve” estratificado
    (2008) Sarmiento Rondón, William B.; Quintana Díaz, Julio C.; College of Arts and Sciences - Sciences; Santana Morant, Dámaris; Lorenzo González, Edgardo; Department of Mathematics; Díaz Rodríguez, Walter
    The inference process is inefficient when employing conventional sampling tech- niques to sample from hidden populations and those of difficult access. The method of sampling by reference or “Link-Tracing” (“Snowball Sampling”) permit provides additional information by using the existing relations or ties among its members, starting from an initial selected sample. In this context the population is presented as a graph, whether directed o not, where each individual is a node that describes its characteristic and each edge, the existing relation between each one of them. From a sociological perspective, human beings form social groups based on particular criterion that could potencially affects parameter estimation. From this point of view, we will apply “Link-Tracing”, by selecting an initial stratified random sampling, instead of an initial simple random sample, in order to increase the precision of our estimates, because the homogeneity intra strata. The objective is to estimate the size and proportion of a hidden population, from an initial sample S0 and S1, identifying each individuals characteristic, and considering the existing relationships, within each stratum. Our second objetive was to develop and implement algorithms in the statistics software R, to be applied to real and simulated data and compare these results to those obtained from conventional sampling procedures.