商务统计公式总结.doc
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lSamplemean
lQ1at(n+1)/4
lQ2at(n+1)/2(themedianposition)
lQ3at3(n+1)/4
lInterquartilerange=Q3–Q1
lSamplevariance
lSamplestandarddeviation
lCoefficientofVariation
lZScore
lPopulationmean
lPopulationvariance
lPopulationstandarddeviation
lChebyshevRule:
atleast(1-1/k2)x100%ofthevalueswillfallwithinμ±kσ
lP(AorB)=P(A)+P(B)-P(AandB)
l
lTwoeventsareindependentifandonlyif:
l
l(IfAandBareindependent)
lselectXobjectsfromnobjects:
(numberofdifferentways)
lselectandarrange:
lExpectedValue(mean)(discretedistribution)
lVarianceofadiscreterandomvariable
lStandardDeviationofadiscreterandomvariable
(Xsuccessesinntrials)
BinomialDistributionMean
Variance
StandardDeviation
Discrete
Probability
Distributions
(l=expectednumberofevents;e=2.71828...)
PoissonDistributionMean
Variance
StandardDeviation
StandardizedNormalDistributiontranslation
oftheMean
(isnormalifpopulation
isnormalorn>30)
SamplingDistributions
oftheProportion
(normaldistributionif
)
σisKnown
forthePopulationMean,μ
ConfidenceIntervalsσisUnknown
ConfidenceIntervalsfor
thePopulationProportion,π
formean
DeterminingSampleSize
forproportion
πcanbeestimatedwithapilotsample(orconservativelyuseπ=0.5)