orthogonal polynomialsorthogonal processorthogonal squaresorthogonal transformationorthogonalityorthogonalization of matricesorthogonally invariant distributionsorthonormal expansionsorthonormal setorthonormal vectorsorthonormalizationoscillatory processosculatory integrationosculatory interpolationostrogorski paradoxostrowski reich theoremoutcomeoutgoingoutlier prone distributionoutliersoutocorrelationoutput dataoutput indexover fittingoverdispersedoverdispersionoverestimationovergraduationoveridentificationoverlapoverlap designoverlapping coefficientoverrepresentationovershoot