Using credibility intervals instead of hypothesis tests in SAGE analysis

MOTIVATION Statistical methods usually used to perform Serial Analysis of Gene Expression (SAGE) analysis are based on hypothesis testing. They answer the biologist's question: 'what are the genes with differential expression greater than r with P-value smaller than P?'. Another useful and not yet explored question is: 'what is the uncertainty in differential expression ratio of a gene?'. RESULTS We have used Bayesian model for SAGE differential gene expression ratios as a more informative alternative to hypothesis tests since it provides credibility intervals. AVAILABILITY The model is implemented in R statistical language script and is available under GNU/GLP copyleft at supplemental web site. SUPPLEMENTARY INFORMATION http://www.ime.usp.br/~rvencio/SAGEci/