suppressionsuppressor variablesupremum normsupremum theoremsurdsure eventsurfacesurprise indexsurrogatesurrogate responsesurveillancesurveysurvey researchsurvey samplingsurvey statisticiansurvey using remote sensingsurvival analysissuspect observationswain fu distanceswampingsweepswindleswingswitch back designswitchingswitching regressionswitching rulesylvester matrixsymbolsymbolic calculussymbolic scattallysymmetric differencesymmetric functionsymmetric meansymmetricalsymmetrical censoringsymmetrical testsymmetrizationsymmetry testsynergismsynthetic estimationsynthetic estimatorsystemsystem of frequency curvessystem of frequency surfacessystem reliabilitysystematicsystematic designsystematic samplingsystems analysis in ecology