@article{Mecatti_2007, title={La stima della media nel campionamento per centri}, volume={62}, url={https://rivista-statistica.unibo.it/article/view/408}, DOI={10.6092/issn.1973-2201/408}, abstractNote={The "aggregation points" sampling design applies, for instance, in survey of irregular immigrants i.e. of populations composed by a finite but unknown number of units which do not consent labelling and that can be reached only through a set of known but overlapping frames called "aggregation points". Dealing with the "aggregation points" sampling design, the problem of estimating the mean of a quantitative character is concerned; an estimate of the estimatorâ€™s variance is also proposed. Some results from a simulation study are presented. Simulations indicate that estimators proposed perform better in case of not too large number of aggregation points but extensively overlapping.}, number={2}, journal={Statistica}, author={Mecatti, Fulvia}, year={2007}, month={Oct.}, pages={285â€“297} }