作者idphobia5566 (idphobia5566)
看板Math
標題[分析] converge in probability
時間Sun Feb 13 22:08:02 2011
iid
X1,...,Xn ~ UNIF(a,b) , a<b , let X(n) be the largest order statistic.
(a)What does exp[X(n)] converge in probability? Show your work.
(b)Find the limiting distribution of exp[-n(b-X(n))/(b-a)] . Show your work.
最大順序統計量之pdf: f_x:n(x) = n(x-a)^n-1/(b-a)^n , a<x<b
想法是
let y = exp(x) , 找出y=exp[X(n)]的pdf,然後用mgf法取極限來求
但這樣不知道怎麼積分...因為式子很難看
f(y)= n{[ln(y)-a]^(n-1)}/[y*(b-a)^n] , exp(a) < y < exp(b)
M_y(t)=E[exp(ty)] 超級難積分
請問有沒有更好的方法可以做,謝謝
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◆ From: 123.193.73.183
→ yhliu :P[X(n)≦z] = [(z-a)/(b-a)]^n when a<z<b 02/13 23:39
→ yhliu :故 X(n) converges in probability to b. 02/13 23:40
→ idphobia5566:是觀察說當n到無窮大時,z=b才會機率是1嗎 02/13 23:49