Dear all, The next seminar in our series of statistics talks for people interested in quantitative methods in biology and medicine will take place on *Thursday 28 November 2013 at 11h00* in the Salle Delachaux (Biopôle 2, premier étage, Route de la Corniche 10, Lausanne, M2: Vennes). The speaker will be *Alina Matei* (University of Neuchâtel) who will speak about "Unequal probability sampling designs, entropy and sample coordination in finite populations" The slides will be in English and the talk in French. Abstract: After a short introduction to unequal probability sampling designs, we show how the sample randomness is related to the Shannon entropy. Higher entropy of a sampling design implies more randomness in sample selection. We present afterwards the unequal probability sampling design, which maximizes the entropy criterion in the class of all possible sampling designs having the same unit inclusion probabilities and a fixed sample size (called maximum fixed-size entropy sampling or Conditional Poisson sampling). Next, we focus on sample coordination, which seeks to create a probabilistic dependence between two or more samples drawn successively or simultaneously from overlapping finite populations. This dependence leads to a maximization or a minimization of the sample overlap. The former is known as positive coordination, and the latter as negative coordination. Positive coordination is mainly employed for estimation purposes and for reasons related to data collection costs. Negative coordination is mainly used to diminish the response burden of the sampled units selected in different samples. We show two schemes to coordinate Conditional Poisson samples. The proposed methods are evaluated using the size of the expected sample overlap, and compared with their competitors, by means of the Monte Carlo simulation. Hope to see you there! Valentin (for the organizers: Jérôme Goudet, Valentin Rousson, Frédéric Schütz) ---------------------------------------------------- Valentin Rousson Unité de Statistique Institut Universitaire de Médecine Sociale et Préventive Centre Hospitalier Universitaire et Université de Lausanne Biopôle 2 Route de la Corniche 10 CH-1010 Lausanne Tél : ++41 (021) 314 73 28 Fax : ++41 (021) 314 73 73 Email: Valentin.Rousson@chuv.chmailto:Valentin.Rousson@chuv.ch