Statistical Bioinformatics Center
Congratulations 2007-2008 Graduates!
Dr. Riyan Cheng and Professor Rebecca W. Doerge
Professor Bruce A. Craig and Dr. Shannon Knapp
Dr. Riyan Cheng performed his Ph.D. research in the area of statisical bioinformatics under the direction of Professors Rebecca W. Doerge and Jun Xie. The title of his thesis was: "Statistical Methods for Mapping Multiple Complex Traits."
Dr. Shannon Knapp performed her Ph.D. research in the area of statistical bioinformatics under the direction of Professor Bruce A. Craig. The title of her dissertation was: "Incorporating Uncertainty into Non-Invasive DNA-Based Mark-Recapture Population Estimates."
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Professor Rebecca W. Doerge Elected Fellow of the American Association for the Advancement of Science
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The cycle of theory, experiment, and information is nowhere more important than in the life sciences, where we are learning how to piece together various levels of expertise into a global or systems-level understanding of biology. Statistical Bioinformatics is involved at each level: accumulation, organization, and analysis of biological data. Hypotheses that are initiated and tested can be refined, and new experiments formulated for the purpose of supplying more information.
Statistical Bioinformatics Center News
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Estimating the Proportion of True Null Hypotheses for Multiple Comparisons
Cancer Informatics. 2008: 4 25-32
Figure 1 (Click on the picture to see a larger image.)
Abstract
Whole genome microarray investigations (e.g. differential expression, differential methylation, ChIP-Chip) provide opportunities to test millions of features in a genome. Traditional multiple comparison procedures such as familywise error rate (FWER) controlling procedures are too conservative. Although false discovery rate (FDR) procedures have been suggested as having greater power, the control itself is not exact and depends on the proportion of true null hypotheses. Because this proportion is unknown, it has to be accurately (small bias, small variance) estimated, preferably using a simple calculation that can be made accessible to the general scientific community. We propose an easy-to-implement method and make the R code available, for estimating the proportion of true null hypotheses. This estimate has relatively small bias and small variance as demonstrated by (simulated and real data) comparing it with four existing procedures. Although presented here in the context of microarrays, this estimate is applicable for many multiple comparison situations.
Hongmei Jiang and R.W. Doerge
