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1、第二章习题部分解答1.解:由矩估计法:8⎧̂1⎪a=X=74.002=∑xi⎪8i=1⎨821⎪σ�=S2=×610−6=www.khdaw.com∑(x−74.002)2i⎪⎩8i=1�2n28−6−6∴S=S=××610=6.85710×n−181−课后答案网2(1)解:由矩估计法:α=A=ξ11'θ2(θ−x)θα=EX=xdx==ξ1∫20θ3∴=θ̂3ξwww.khdaw.comα=A=ξ11(2)'1θθ+1α=EX=x(θ+1)xdx==ξ1∫0θ+2̂2ξ课后答案网−1∴=θ1−ξ(3)x−θ
2、1−+∞1θα=e2⋅xdx=θ+θ=ξ1∫12θ1θ2x−θ1−n+∞1θ1α=∫e2⋅xdx2=A=∑X2=θ2+2θξ22i12θ1θ2ni=12www.khdaw.com2̂2∴A=S+ξ=θ=(ξθ−)+2θξ222⎧⎪θ=−ξS1∴⎨⎪⎩θ=S2课后答案网N1NN(+1)1(4)A1=ξ=∑xi=⋅i=1N2N⇒N�=2ξ−1(5)1θ−1θA=ξ=xθxdx=1∫0θ+1̂ξ2www.khdaw.com⇒θ=()ξ−1∞2k−22(6)A=ξ=∑kki(−1)θ(1−θ)=1k=2θ2课后答案网
3、⇒θ̂=ξ3.解:设A={ξ<0},X表示A出现的次数,2(xa−)01−PA()=P{ξ<0}=∫e2dx−∞2πξ−a0−awww.khdaw.com=P{<}=Φ−(a)=p≈0.7,11∴p≈0.7,a=−0.525课后答案网4.解:nθ−(θ+1)(1)()Lθ=∏θcxii=1nln()Lθ=∑[lnθθ+lnc−(θ+1)ln]xii=1nn∂ln()Lθ1θ=∑[+lnc−ln]www.khdaw.comxi=+nlnc−∑lnxi=0∂θi=1θni=1̂nθ=n∑lnxi−nlnci=1课
4、后答案网nθ−1(2)()Lθ=∏θxii=1nln()Lθ=∑[lnθ+(θ−1)ln]xii=1n∂ln()Lθ111=∑[+ln]0xi=∂θi=1θ2θ2θ2̂nwww.khdaw.comθ=n2(∑ln)xii=1课后答案网n11(3)()Lθ=∏=ni=1θθln()Lθ=−nlnθ∂ln()Lθn=−=0∂θθ⎧1⎧1⎪,,ξ…,ξ≤θ⎪,ξ≤θn1nn()n∵L()θ=⎨θwww.khdaw.com=⎨θ⎪⎩0,other⎪⎩0,other11≤,()Lθ≤L(ξ)nn()nθξ()n课后答案
5、网θ̂=ξ()nn(4)()Lθ=∏Cxiθxi(1−θ)Nx−iNi=1nxiln()Lθ=∑[lnCN+xilnθ+(N−xi)ln(1−θ)]i=1nn∑xi∑(N−xi)∂ln()Lθi=1i=1=−www.khdaw.com=0∂θθ1−θ̂xθ=N课后答案网n121−2(xi−θ)(5)()Lθ=∏e2θi=1θ2πn2(x−θ)iln()Lθ=∑[ln2πθ−]2i=12θn22∂ln()Lθ−2πn−2(x−θθ)−2(x−θθ)ii=∑[=04∂θ2πθi=1www.khdaw.com2θ2
6、n̂ξ12ξθ=+∑ξi−4ni=12课后答案网nc−(c+1)(6)()Lθ=∏cθxii=1nln()Lθ=∑[lncc−lnθ−(c+1)ln]xii=1∂ln()Lθnĉ=−=0不能解出θ,所以由∂θθnwww.khdaw.com̂c−(c+1)L()θ=∏cθxi,θ≤ξ1,…,ξni=1L()θ≤L(ξ)⇒θ̂=ξ(1)(1)课后答案网n2xi−2(7)()Lθ=∏(xi−1)θ(1−θ)i=1nln()Lθ=∑[2lnθ+(xi−2)ln(1−θ)ln(+xi−1)]i=1n∑xi−2n∂ln
7、()Lθ2n2i=1̂=−]0=⇒θ=∂θθ1−θξwww.khdaw.comn(8)()Lθ=∏θδ()xi(2)θδ(xi−1)(13)−θδ(xi−2)=θn0(2)(13)θn1−θn2i=1∂ln()Lθ̂2−ξ=⇒0θ=∂θ课后答案网45.解:∵ξ~U(,0)θn11(1)()Lθ=∏−=n,θ<ξ1,…,ξn<0i=1θ(−θ)θ̂max=ξ,()Lθ≤L()θ̂(1)∵ξ~U(,2)θθwww.khdaw.comn11(2)()Lθ=∏=n,θ<ξ1,…,ξn<2θi=1θθξξξθ̂=()n
8、,()Lθ≤L(),θ̂1,…,n<θmin2课后答案网22nn6.解:1−x−θ(1)()Lθ=∏fx(,)θ=∏eiii=1i=12x,…,xx<⋯9、xi−θ
10、1∑x()k−∑x()l+(n−2)iθL()θ=ei=1=ek=1li=+1nn22⎧ξ,n为奇www.khdaw.comn+1()⎪2̂⎪θ=⎨ξ+ξ时L()θ达到最大值