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Title: Thinking Out of the Sample: Estimation of Small Tail Probabilities in Food Safety and Bio-Surveillance

  • Speaker: Professor Benjamin Kedem, Department of Mathematics & Institute For Systems Research, University of Maryland, College Park
  • Date: Friday, January 24, 2014
  • Time: 3:15 pm
  • Location: St. Mary's 326, Georgetown University, Washington, DC.
  • Directions: maps.georgetown.edu
  • Sponsor: Department of Mathematics and Statistics, Georgetown University (math.georgetown.edu)


In food safety and bio-surveillance in many cases it is often desired to estimate the probability that a contaminant such as some insecticide or pesticide exceeds unsafe very high thresholds. The probability or chance in question is then very small. To estimate such a probability we need information about large values. However, in many cases the data do not contain information about exceedingly large contamination levels, which ostensibly makes the problem impossible to solve. A solution is provided whereby more information about small tail probabilities is obtained by combining the real data with computer generated random data. The method provides short but reliable interval estimates from moderately large samples. Examples are given in terms of DDT derivatives and chlorpyrifos found in fish, mussel, and sediments, and in terms of mercury levels obtained from males and females of all ages.