商务统计学（第7版）英文ppt课件5 Discrete Probability Distributions 、6 The Normal Distribution .ppt

DiscreteProbabilityDistributionsChapter5

ObjectivesInthischapter,youlearn:Thepropertiesofaprobabilitydistribution.Tocomputetheexpectedvalueandvarianceofaprobabilitydistribution.Tocomputeprobabilitiesfrombinomial,andPoissondistributions.Tousethebinomial,andPoissondistributionstosolvebusinessproblems

DefinitionsDiscretevariablesproduceoutcomesthatcomefromacountingprocess(e.g.numberofclassesyouaretaking).Continuousvariablesproduceoutcomesthatcomefromameasurement(e.g.yourannualsalary,oryourweight).

TypesOfVariablesCh.5Ch.6Ch.5Ch.6TypesOfVariablesDiscreteVariableContinuousVariableCh.5Ch.6

DiscreteVariablesCanonlyassumeacountablenumberofvaluesExamples:Rolladietwice LetXbethenumberoftimes4occurs (thenXcouldbe0,1,or2times)Tossacoin5times. LetXbethenumberofheads(thenX=0,1,2,3,4,or5)

ProbabilityDistributionForADiscreteVariableAprobabilitydistributionforadiscretevariableisamutuallyexclusivelistingofallpossiblenumericaloutcomesforthatvariableandaprobabilityofoccurrenceassociatedwitheachoutcome.InterruptionsPerDayInComputerNetworkProbability00.3510.2520.2030.1040.0550.05

ProbabilityDistributionsAreOftenRepresentedGraphicallyP(X)0.40.30.20.10 1 2 3 4 5 X

DiscreteVariablesExpectedValue(MeasuringCenter)ExpectedValue(ormean)ofadiscretevariable(WeightedAverage)InterruptionsPerDayInComputerNetwork(xi)ProbabilityP(X=xi)xiP(X=xi)00.35(0)(0.35)=0.0010.25(1)(0.25)=0.2520.20(2)(0.20)=0.4030.10(3)(0.10)=0.3040.05(4)(0.05)=0.2050.05(5)(0.05)=0.251.00μ=E(X)=1.40

VarianceofadiscretevariableStandardDeviationofadiscretevariable where: E(X)=ExpectedvalueofthediscretevariableX xi=theithoutcomeofX P(X=xi)=ProbabilityoftheithoccurrenceofXDiscreteVariables:

MeasuringDispersion

DiscreteVariables:

MeasuringDis