title: Comparison of statistical significance criteria.
abstract: We study and compare two classes of statistical criteria to assess the significance of exceptional words. Indeed, the Z-score-like criteria, or the normal approximation that is a strict equivalent, suffer from several drawbacks in terms of sensitivity and specificity. Thanks to the combinatorial structure of words, a computation of the exact P-value has been made possible by recent mathematical results. We study here the drawbacks of the Z-score, the choice of the threshold and the tightness to the P-value. A major conclusion is that the normal approximation is always very poor and overestimates statistical significance.
authors.affiliation: INRIA, 78153 Le Chesnay, France. Mireille.Regnier@inria.fr
authors.forename: Mireille
authors.initials: M
authors.lastname: Régnier
authors.forename: Mathias
authors.initials: M
authors.lastname: Vandenbogaert
mesh_terms: D000465:Algorithms; D001483:Base Sequence; D001665:Binding Sites; D002874:Chromosome Mapping / Q000379:methods*; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D019277:Entropy; D008957:Models, Genetic; D015233:Models, Statistical; D008969:Molecular Sequence Data; D016415:Sequence Alignment / Q000379:methods*; D017422:Sequence Analysis, DNA / Q000379:methods*; D012984:Software; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D014157:Transcription Factors