<div dir="ltr"><br><div class="gmail_quote"><div dir="ltr"><span lang="EN-US"></span><br><span lang="EN-US"></span><div class="gmail_quote"><div dir="ltr"><div><p class="MsoNormal" style="margin:0cm 0cm 10pt;line-height:115%;font-size:11pt;font-family:"Calibri","sans-serif""><span lang="EN-US">
<br>
</span><b><span style="font-size:12pt;line-height:115%" lang="EN-US"><span></span></span></b></p>

<p class="MsoNormal" style="margin:0cm 0cm 10pt;line-height:115%;font-size:11pt;font-family:"Calibri","sans-serif""><b><span style="font-size:12pt;line-height:115%" lang="EN-US">Probability
Webinar - UFRJ <span></span></span></b></p>

<p class="MsoNormal" style="margin:0cm 0cm 10pt;line-height:115%;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;line-height:115%" lang="EN-US"><span> </span></span></p>

<p class="MsoNormal" style="margin:0cm 0cm 10pt;line-height:115%;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;line-height:115%" lang="EN-US">Dear colleagues, <span> </span><span></span></span></p>

<p class="MsoNormal" style="margin:0cm 0cm 10pt;line-height:115%;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;line-height:115%" lang="EN-US">Our next online seminar will be held next Monday, July
13, from <b>3 p.m. to 4 p.m</b>. (Rio de Janeiro local time)<span></span></span></p>

<p class="MsoNormal" style="margin:0cm 0cm 10pt;line-height:115%;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;line-height:115%" lang="EN-US">The GoogleMeet link for the seminars is: </span><span style="font-size:12pt;line-height:115%"><a href="https://meet.google.com/nxh-optr-wtq" style="color:blue;text-decoration:underline" target="_blank"><span lang="EN-US">https://meet.google.com/nxh-optr-wtq</span></a></span><span style="font-size:12pt;line-height:115%" lang="EN-US"> 
<br>
<br>
<span></span></span></p>

<p class="MsoNormal" style="margin:0cm 0cm 10pt;line-height:115%;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;line-height:115%" lang="EN-US">Speaker: <b><span style="font-family:"Calibri","sans-serif";font-weight:normal">Rafael Izbicki (UFSCar)</span></b><br>
<br>
</span><span style="font-size:12pt;line-height:115%" lang="EN-US">Title:</span><span style="font-size:12pt;line-height:115%" lang="EN-US"> Quantification under prior probability
shift: the ratio estimator and its extensions <span></span></span></p>

<p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;line-height:normal;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt" lang="EN-US"><span> </span></span></p>

<p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;line-height:normal;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt" lang="EN-US">Abstract:<b> </b></span><span style="font-size:12pt" lang="EN-US">The
quantification problem consists of determining the prevalence of a given label
in a target population using labels from a sample from the training population.
A common assumption in this situation is that of prior probability shift, that
is, once the labels are known, the distribution of the features is the same in
the training and target populations. In this paper, we derive a new lower bound
for the risk of the quantification problem under the prior shift assumption.
Complementing this lower bound, we present a new approximately minimax class of
estimators, ratio estimators, which generalize several previous proposals in
the literature. Using a weaker version of the prior shift assumption, which can
be tested, we show that ratio estimators can be used to build confidence
intervals for the quantification problem. We also extend the ratio estimator so
that it can:(i) incorporate labels from the target population, when they are
available and (ii) estimate how the prevalence of positive labels varies
according to a function of certain covariates.<span></span></span></p>

<p class="MsoNormal" style="margin:0cm 0cm 10pt;line-height:115%;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;line-height:115%" lang="EN-US"><span> </span></span></p>

<p class="MsoNormal" style="margin:0cm 0cm 10pt;line-height:115%;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;line-height:115%" lang="EN-US">Thanks for circulating this information. <span></span></span></p>

<p class="MsoNormal" style="margin:0cm 0cm 10pt;line-height:115%;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;line-height:115%" lang="EN-US">Sincerely, <br>
<br>
<span></span></span></p>

<p class="MsoNormal" style="margin:0cm 0cm 10pt;line-height:115%;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;line-height:115%" lang="EN-US">Organizers: Guilherme Ost and
Maria Eulalia Vares<span></span></span></p>





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