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Fall 2007
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Kwang Woo Ahn
PhD Candidate in Statistics
University of Iowa
"Bayesian Inference with Incomplete Multinomial Data - Assessing the Spatio-Temporal Variation in Pathogen-Variant Diversity"
3:00 Refreshments in 241 Schaeffer Hall
3:30 Talk in 140 Schaeffer Hall
With recent advance in genetic analysis, it is feasible to classify a pathogen into genetically
distinct variants. The availability of such data opens up the interesting question of studying
the spatial-temporal diversity of the variants of a pathogen. Data on pathogen variants often
suffer from some data problems including (i) low cell counts, (ii) incomplete classification,
and (iii) unseen variants. We adopt the Shannon entropy as a measure of pathogen diversity,
and propose a Bayesian approach that can handle the problems of low cell counts and
unseen variants. The existence of incomplete data generally complicates statistical inference
that may have to rely on Markov chain Monte Carlo methods such as the Gibbs sampler.
However, for incomplete multinomial data with disjoint sources of missingness, we show
that, with a suitable re-parameterization, the posterior distribution admits an independent
sampling scheme. We extend this idea to develop an efficient block Gibbs sampler for general
incomplete multinomial data having possibly overlapping sources of missingness. The
proposed methods will be illustrated with simulated and real data.
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All talks are free and open to the public.
To receive colloquium reminders via email, please send a request to statistics@uiowa.edu.
The 37th Annual Craig Lectures will be on October 11 and 12. Our speaker this year is Nancy Reid from the University of Toronto.
Past colloquia:
Spring 2007 |
Fall 2006 | Spring 2006 |
Fall 2005 |
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