统计专业英语教案 常用统计学术语复习

一、统计学术语

population总体

sample样本

census普查

sampling抽样

quantitative量的

qualitative质的

discrete离散的

continuous连续的

populationparameters总体参数

samplestatistics样本统计量

descriptivestatistics叙述统计学

抽样调查samplingsurvey

简单随机抽样simplerandomsampling

系统抽样systematicsampling

分层抽样stratifiedsampling

整群抽样clustersampling

多级抽样multistagesampling

实验设计DesignofExperiment)

参数Parameter

Statistics统计学

Statisticaltable统计表

Statisticalchart统计图

Piechart圆饼图

Stem-and-leafdisplay茎叶图

Histogram直方图

BarChart长条图

Polygon多边形

Expectation期望值

Mode众数

Mean平均数

Variance变异数

Standarddeviation标准差

Standarderror标准误

Inferentialstatistics推论统计学

Pointestimation点估计

Intervalestimation区间估计

Confidenceinterval置信区间

Confidencecoefficient置信系数

Regressionanalysis回归分析

Analysisofvariance变异数分析

Correlationcoefficient相关系数

Reliability信度

Validity效度

Discreteuniformdensities离散的均匀密度

Binomialdensities二项密度

Hypergeometricdensities超几何密度

Poissondensities卜松密度

Geometricdensities几何密度

Negativebinomialdensities负二项密度

Continuousuniformdensities连续均匀密度

Normaldensities正态密度（分布）

Exponentialdensities指数密度

Gammadensities伽玛密度

Betadensities贝他密度

Multivariateanalysis多变量分析

Principalcomponents主因子分析

Discriminationanalysis判另U分析

Clusteranalysis群集分析

Factoranalysis因素分析

Survivalanalysis存活分析

Timeseriesanalysis时间序列分析

Linearmodels线性模式

Probabilitytheory概率率论

Statisticalinference统计推论

Stochasticprocesses随机过程

Decisiontheory决策理论

Discreteanalysis离散分析

Mathematicalstatistics数理统计

相关系数:Correlationcoefficient

算术平均数(ArithmeticMean)

元素(Element)邮寄问卷法(MailInterview)

封闭式问题(CloseQuestion)

电话访问法(TelephoneInterview)

市场调查(MarketingResearch)

决策树(DecisionTrees)

容忍误差(Toleratederro)

数据挖掘(DataMining)

初级资料(PrimaryData)

趋势分析(TrendAnalysis)

神经网络(NeuralNetwork)

人员访问法(Interview)判别分析法(DiscriminantAnalysis)

集群分析法(clusteranalysis)规则归纳法(RulesInduction)

内容效度(ContentValidity)判断抽样(JudgmentSampling)

二、阅读资料

Frequency

Whencollectinginformation,forinstancethecolorofcarsinacar

park,therewillberepeatedexamplesofparticularcolors.Theremaybe

fouryellowcars,13redcars,eightbluecarsand20carsofothercolors.

Theinformationisqualitative.Thenumberofcarsofeachcoloristhe

frequencyofobservationofthatitemofinformation.

Inevitableingatheringanyinformationtherewillbeacollectionof

frequenciesassociatedwithitemsofdata.Thefrequenciesarenotonly

thedata,theytellussomethingaboutthedistributionofthedata.

Presentationofdata(1)

Qualitativedatamaybepresentedinafrequencytablesuchasthe

onebelow.

Amongthemanyconsiderations,itwouldbeimportanttohavesome

ideasofwhatatypicaltimewaslikelytobe,andthelikelyrangeoftimes.

Thisinformationisnecessarysothatanappropriatetimingdevicecanbe

selected.Therewouldbelittlepointintryingtouseawatch'sminute

handoranelectronictimercapableofrecordingto1/1000ofasecond.It

isalsounlikelytobenecessarytorecordtimesaslongasanhour,butthe

timerneedstobecapableofrecordingmorethanafewseconds.

Therearetwomeasuresrepresentativeofdatawhichmaybeuseful

incaselikethis-onerepresentingthe'typicalvalue5andanotherwhich

indicatesthe'sortofrangeofvalue5likelytobefound.Instatisticalterms,

thesearemeasuresoflocationoraverageanddispersionorspread.

Lifewouldbesimpleiftherewerejustoneofeach,orevenanideal

measureofeachquality.Unfortunately,thisisnotthecase.Thereare

manytypesofaverageandseveralkindsofspread.Inthischapterwe

shallconcentrateonaverages.

Mode

Themodeisthemostcommonlyoccurringvalueoritemofdate,or,

inotherwords,theonethatappearsmostfrequently.Inthecontextofthe

dataunderconsideration,themostcommonlyoccurringvalueis9

seconds.Isitreasonable,though,toconsider9secondsasbeingtypical

ofthetimetakentopassthroughthiscontinentalmotorwaytoll?

Almostcertainlynot!Itmanybemoreappropriatetoconsiderthemodal

class.Referringbacktothediagram,the1-branchhasthegreatest

frequency.Hence,itwouldbereasonabletosaythatthemodeisthetime

between20and30seconds.Thisisthelongestbranchinthe

stem-and-leafdiagram.

Themodalclassmaybetheclasswiththehighestfrequencywhen

thedataarepresentedinafrequencytable,butitmaynot!

Theprominenceofthe20-30secondsclassisapparent.Themethod

assumesthatthemodedividesthemodalclassinthesameratioasthe

increaseinfrequencydensitytothedecreaseinfrequencydensity.Inthe

frequencytable,thisratiois(9-7):(9-6),whichisequivalentto2:3.Hence

themodedividesthemodalclassintheratio2:3,andanestimateofthe

modeis24.Weneedtoaskourselves,howvalidisthisprocess?

WhereWisthewidthofthemodalclass,andxisitslowerbound.

Intheexample,1=2,D=3,W=10andx=20.

Hereestimateofthemode=20+(2/5)*10=24.

Median

Step-by-step

Thecentreormiddleitemofthedataisknownasthemedian.One

approachtoidentifyingthemedianisto:

■placethedatainorder

■locatethemiddleitem

■hence,identifythemedian

Supposeweneedtoidentifythemedianofthefollowingcollection

ofdata.

8,15,7,10,4,3,8,6,5,7,8

Placingthedatainorderyields:

3,4,5,6,7,7,8,8,8,10,15

Themiddleitemistheonewhichisequidistantfromtheextreme

values.

Sincethereareelevenitemsofdata,themiddleisthesixthfrom

eitherend.

Eventotal

Forthecollectionabove,thetotalnumberofitemsisodd,whichled

tothemedianbeingoneoftheactualrecordeditemsofdata.Inthe

followingcase,thetotalisanevennumber,whichmeansthecentervalue

ofthedataismidwaybetweentwooftherecordeditems.

4,5,0,3,9,4,8,9,9,1

Orderingthedatagives:

0,1,3,4,4,5,8,9,9,9

andlocatingthemiddlevalueyields:

Groupedfrequencytable

Ifthedataarepresentedinafrequencytable,thenitisonlypossible

toobtainanestimateofthemedian.Thisisdoneeithergraphicallyor

arithmetically.

Thecumulativefrequenciesforthefrequencytableisgivenbelow.

TimeFrequencyCumulativefrequency

[0,10)44

[10,20)711

[20,30)920

[30,40)626

[40,50)531

[50,60)334

[60,120)943

Groupedfrequencytable

Whatinformationcanbegainedfromthecumulative

frequency?

Considerthecumulativefrequencyof20.thistellsusthatthereare

20itemsofdatawithvalueslessthan30.Similarly,thecumulative

frequencyof34indicatesthatthereare34itemswhicharelessthan60.

Thereisanaturallinkbetweenanygivencumulativefrequencyandthe

upperboundofthecorrespondingclass.Hence,whenitcomesto

constructingacumulativefrequencygraph,thepointstobeplottedcome

fromthefollowingseriesdata.

Range

Perhapsthemostsimplemeasureofspreadisthedifferencebetween

thelargestandsmallestitemsofdatai.e.thedifferencebetweenthe

extremes.Thisistherange.Inthecaseofthemotorwaytolltimesthe

longesttimerecordedwas118secondsandtheshortesttimewas9

seconds,hencetherangeofthesedataisgivenby:

range=118-9-109seconds

Thismeasureofspreaddosenottakeintoaccountanythingabout

thedistributionofthedataotherthantheextremes.Neitherisitvery

reliableortypical.Why?

Quartilespread

Amoretrustworthymeasureistherangeofthemiddlehalfofthe

data.Toidentifythisrangeweneedtofindtheitemsofdatawhichare

positionedhalfwaybetweentheextremesandthemedian.Takethecase

ofthedatafollowing:

Ingeneral,theitemsofdatalyingmidwaybetweenthemedianand

theextremesareknowasthequartiles.Itismoreusualtorefertothemas

thefirstorlowerquartileandthethirdorupperquartile.Thedifference

betweenthemiscalledtheinterquartilerange(IQR)orquartilespread

(QS)

Standarddeviation

Theinterquartilerangemeasuresthespreadofthemiddlehalfofthe

dataandiscloselylinkedtothemedian.Wecandefineameasureof

dispersion,takingintoaccountallthedata,whichislinkedinsteadtothe

mean.

Deviationfromthemean

Supposetheitemsofdata:18,20,21,22,24.

Themeanofthecollectiondatais21,hencethedeviationfromthe

meanare:-3,-1,0,1,3,andtheaverage(ormean)ofthisdeviationsis

theirsumdividedbythenumberofitems.Thisc