中国民航大学《概率论与数理统计》期末考试试题及答案B[1]

Internet迅速发展无所不在以及诱人的低价位，的确令众多厂商开始采用这种办法，但Internet天生的开放性特点令人无所适从，安全性又成了问题，公司的机密数据一旦在Internet传输，若没有安全性保障，其后果可想而知。villagetemplesCentralOfficeeveryday,carryouttheirduties.CorrespondencerelatingtoeducationbytheChiefofthefirstsectionmarkedmydraftstatement.Workedafterafewmonths,I'vebeenburiedintheofficialprogram,veryrigidmonotonyofclericalcareer,flavourless.1939of7Augustbetween,County,andSecretarytoIwithtoOfficemeeting,forGovernmentestablishedoneyearstoworkreported,fortimerush,priornotforfullprepared,hadtoinwaybyrankAnnMrdescribedoneyearstoaboutpeople,andfiscal,andbuilt,andtaught,andinsurancefiveaspectsimportantmatters,Iaccordinglydetailednarrativefinishingwritten,completedWujiangGovernmentestablishedoneyearstoofworkreport.TurnbackandforthmonthShanRoad,apartfromtheSecretary,Mrrankfootdiseaseimmobility,bamboocarinsteadofwalkingoutside,squarefoot(exceptformyselfand4guards),thewuxing,peace,SIan,Guangde,doorwayswing,ZhangZhutothedestination--wearingBu.Atdiweitotheimportanttownsoftroopsisdifficulttoaccess,wehavetochangeangles,Shanruggedtrails,Sunandrainontheway,hardshipexceptions,ifthepatrioticandpassionsofthewar,thanthesuccessfulcompletionoftasks.Anoldfrail,rank,long-distanceLawtonregrets,admirable!InNovember1939,IwasadmittedtotheFacultyoflaw,CollegeoflawandpoliticsinShanghai,butresignedfromthepostoffice,bidfarewelltothisshortandmemorablelife.(J)thesiazhenboatburiedJapanesemorningofOctober18,1937,siazhensicktoshunTangQiao-cutters,1fromNanxuntownjiaxingtoJapaneseboats,caughtdraggingbehind3smallboats,loadedwithmilitarygoods.Siazhentoolatetoescape,jumpedashoreJapancatchupwiththeboat,forcinghimtorowaboat.MeanwhilecaughtthemigrantsvillageZhangShun.Siazhenwassickforalongtime,《概率论与数理统计》期末考试试题一、填空题（每题3分，共15分）1、已知随机变量X服从参数为2的泊松（Poisson）分布，且随机变量22XZ，则ZE____________．2、设A、B是随机事件，7.0AP，3.0BAP，则ABP3、设二维随机变量YX,的分布列为若X与Y相互独立，则、的值分别为。4、设4,1,,0.6DXDYRXY，则DXY____5、设12,,,nXXX是取自总体),(2N的样本，则统计量2211()niiX服从__________分布.二、选择题（每题3分，共15分）1.一盒产品中有a只正品，b只次品，有放回地任取两次，第二次取到正品的概率为【】(A)11aab；(B)(1)()(1)aaabab；(C)aab；(D)2aab.2、设事件A与B互不相容，且0AP，0BP，则下面结论正确的是【】(A)A与B互不相容;(B)0ABP;(C)BPAPABP;(D)APBAP.3、设两个相互独立的随机变量X与Y分别服从正态分布1,0N和1,1N，则【】(A)210YXP；(B)211YXP；(C)210YXP；(D)211YXP。YX12316191181231Internet迅速发展无所不在以及诱人的低价位，的确令众多厂商开始采用这种办法，但Internet天生的开放性特点令人无所适从，安全性又成了问题，公司的机密数据一旦在Internet传输，若没有安全性保障，其后果可想而知。villagetemplesCentralOfficeeveryday,carryouttheirduties.CorrespondencerelatingtoeducationbytheChiefofthefirstsectionmarkedmydraftstatement.Workedafterafewmonths,I'vebeenburiedintheofficialprogram,veryrigidmonotonyofclericalcareer,flavourless.1939of7Augustbetween,County,andSecretarytoIwithtoOfficemeeting,forGovernmentestablishedoneyearstoworkreported,fortimerush,priornotforfullprepared,hadtoinwaybyrankAnnMrdescribedoneyearstoaboutpeople,andfiscal,andbuilt,andtaught,andinsurancefiveaspectsimportantmatters,Iaccordinglydetailednarrativefinishingwritten,completedWujiangGovernmentestablishedoneyearstoofworkreport.TurnbackandforthmonthShanRoad,apartfromtheSecretary,Mrrankfootdiseaseimmobility,bamboocarinsteadofwalkingoutside,squarefoot(exceptformyselfand4guards),thewuxing,peace,SIan,Guangde,doorwayswing,ZhangZhutothedestination--wearingBu.Atdiweitotheimportanttownsoftroopsisdifficulttoaccess,wehavetochangeangles,Shanruggedtrails,Sunandrainontheway,hardshipexceptions,ifthepatrioticandpassionsofthewar,thanthesuccessfulcompletionoftasks.Anoldfrail,rank,long-distanceLawtonregrets,admirable!InNovember1939,IwasadmittedtotheFacultyoflaw,CollegeoflawandpoliticsinShanghai,butresignedfromthepostoffice,bidfarewelltothisshortandmemorablelife.(J)thesiazhenboatburiedJapanesemorningofOctober18,1937,siazhensicktoshunTangQiao-cutters,1fromNanxuntownjiaxingtoJapaneseboats,caughtdraggingbehind3smallboats,loadedwithmilitarygoods.Siazhentoolatetoescape,jumpedashoreJapancatchupwiththeboat,forcinghimtorowaboat.MeanwhilecaughtthemigrantsvillageZhangShun.Siazhenwassickforalongtime,4、如果YX,满足YXDYXD)(，则必有【】（A）X与Y独立；（B）X与Y不相关；（C）0DY；（D）0DX5、设相互独立的两个随机变量X与Y具有同一分布律，且X的分布律为则随机变量YXZ,max的分布律为【】(A)211,210zPzP；(B)01,10zPzP；(C)431,410zPzP；(D)411,430zPzP。三、解答题（共30分）1.（本题满分8分）两台机床加工同样的零件，第一台出现废品的概率为0.03，第二台出现废品的概率为0.02，已知第一台加工的零件比第二台加工的零件多一倍，加工出来的零件放在一起，求：任意取出的零件是合格品(A)的概率.2.（本题满分8分）将一枚硬币连掷三次，X表示三次中出现正面的次数，Y表示三次中出现正面次数与出现反面次数之差的绝对值，求：（1）（X，Y）的联合概率分布；（2）XYP.3.（本题满分10分）设随机变量1,0~NX，12XY，试求随机变量Y的密度函数．四、（8分）设X的密度函数为),(,21)(xexfx①求X的数学期望()EX和方差()DX；②求X与X的协方差和相关系数，并讨论X与X是否相关？五、（本题满分8分）二维随机变量（X，Y）的概率密度为其他,00,0,),()2(yxAeyxfyx求：（1）系数A；（2）X，Y的边缘密度函数；（3）问X，Y是否独立。六、（本题满分12分）设总体2~，NX，其中是已知参数，02是未知参数．nXXX，，，21是从该总体中抽取的一个样本，⑴.求未知参数2的极大似然估计量2ˆ；⑵.判断2ˆ是否为未知参数2的无偏估计．X01P2121Internet迅速发展无所不在以及诱人的低价位，的确令众多厂商开始采用这种办法，但Internet天生的开放性特点令人无所适从，安全性又成了问题，公司的机密数据一旦在Internet传输，若没有安全性保障，其后果可想而知。villagetemplesCentralOfficeeveryday,carryouttheirduties.CorrespondencerelatingtoeducationbytheChiefofthefirstsectionmarkedmydraftstatement.Workedafterafewmonths,I