<div dir="ltr">Slides disponíveis em<div><br></div><div><a href="https://www.youtube.com/watch?v=DwUYy05r1_k" target="_blank" style="font-size:12.8px">https://www.youtube.com/watch?<wbr>v=DwUYy05r1_k</a><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Aug 1, 2017 at 9:10 AM, Clarice Garcia Borges Demetrio <span dir="ltr"><<a href="mailto:clarice.demetrio@usp.br" target="_blank">clarice.demetrio@usp.br</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div><div style="font-size:12.8px"><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI">Segue a divulgação do <span class="m_-3597458512009023233m_-2672201049412458125gmail-il">Seminário</span> que será ministrado pelo Prof. Dr. John Hinde, no dia <font size="4">02/08/2017, às 14 horas,</font> no Departamento de Ciências Exatas, ESALQ/USP.<br><br></span></div><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI" style="font-size:12.8px"><br><br></span><div style="font-size:12.8px;text-align:center"><div><b><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI">Over/Under-dispersion, zero-inf</span><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI">ation and Poisson-Tweedie </span><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI">models</span></b><br><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI"><span class="m_-3597458512009023233m_-2672201049412458125gmail-il">John</span> Hinde1, Clarice Demétrio2 and Wagner Bonat3</span><span class=""><br><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI">1School of Mathematics, Statistics and Applied Mathematics, National University</span><br><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI">of Ireland, Galway, Ireland</span><br><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI">2ESALQ/USP, Piracicaba, Brazil</span><br><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI">3Paran a Federal University, Curitiba , Brazil</span><br><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI">Email: <a href="mailto:john.hinde@nuigalway.ie" target="_blank"><span class="m_-3597458512009023233m_-2672201049412458125gmail-il">john</span>.hinde@nuigalway.ie</a><br><br></span></span></div><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI"></span></div><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI" style="font-size:12.8px"><span class=""><b>Abstract</b>: The standard distributions for the analysis of count and proportion data<br>are the Poisson and binomial distributions. Frequently, in practice they are too<br>restrictive in that the variability in the data is either signicantly greater (overdis-<br>persed) or less (underdispersed) than that implied by the models variance function.<br>For the analysis of count data, Nelder and McCullagh (1989) says that overdisper-<br>sion is the norm and not the exception and this has been well studied, see Hinde and<br></span>Demétrio (1999) and many subsequent articles presenting a wide range of distribu-<span class=""><br>tions. Although less common, underdispersion can arise, typically from dependent<br>responses. For instance, when there is competition between plants and animals this<br>can induce negative correlation in temporal and spatial counting processes. Here we<br>will also consider how underdispersion can occur as a result of features of the under-<br>lying counting, or data collection, process. The range of distributions for modelling<br>underdispersed count data is relatively limited, although models can be derived in<br>specic situations.<br>A class of general models is presented based on Poisson-Tweedie factorial dispersion<br></span>models with variance phi mu^p, where mu is the mean, phi and p are the dispersion and<br>Tweedie power parameters, respectively. This class of models provides a flexible and<span class=""><br>comprehensive family including many standard discrete models. The family provides<br>for modelling of overdispersed count data, including Neyman Type A, Polya-Aeppli,<br>negative binomial, Poisson-inverse Gaussian and Hermite distributions, and can<br></span>also accommodate zero-infation and underdispersion. For a general approach we<span class=""><br>consider an extended version of the Poisson-Tweedie model and discuss estimation<br>of regression, dispersion and Tweedie power (variance function) parameters. A full<br>description of the approach is given in Bonat et al. (2017).<br><br>References<br></span>Bonat, W., J rgensen, B, Kokonendji, C., Hinde, J. and Demétrio, C.G.B. (2017)<br>Extended Poisson-Tweedie: properties and regression models for count data. Statistical Modelling</span></div><div><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI" style="font-size:12.8px">(accepted)</span></div><div><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI" style="font-size:12.8px"><br>Hinde, J. and Demétrio, C.G.B. (1998) Overdispersion: Models and estimation. </span></div><div><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI" style="font-size:12.8px">Computational Statistics and Data Analysis. 27, 151{170.</span></div><span class=""><div><span class="m_-3597458512009023233m_-2672201049412458125gmail-m_-2251458849292252161gmail-gI" style="font-size:12.8px"><br>McCullagh, P. and Nelder, J.A. (1989). Generalized Linear Models. Chapman and<br>Hall.</span><br><div><br></div><div><br><div><br></div><div><br></div><div><br></div><div><br></div></div></div></span></div> </div><br></div><div id="m_-3597458512009023233DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2"><br> <table style="border-top:1px solid #d3d4de"> <tbody><tr> <td style="width:55px;padding-top:18px"><a href="https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail" target="_blank"><img src="https://ipmcdn.avast.com/images/icons/icon-envelope-tick-round-orange-animated-no-repeat-v1.gif" alt="" width="46" height="29" style="width:46px;height:29px"></a></td> <td style="width:470px;padding-top:17px;color:#41424e;font-size:13px;font-family:Arial,Helvetica,sans-serif;line-height:18px">Livre de vírus. <a href="https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail" style="color:#4453ea" target="_blank">www.avast.com</a>. </td> </tr> </tbody></table> <a href="#m_-3597458512009023233_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2" width="1" height="1"></a></div> </blockquote></div><br></div>