設 隨機變數 X 與 Y 聯合機率密度函數
x(y+1.5) , 0 < x < 1 , 0 < y < 1
fX,Y(x,y)=
0 , ow
(一)求 E[X]
1 1
擬答： ∫∫x^2(y+1.5)dxdy = ∫x^2dx ∫y+1.5 dy = 1/3 (2) = 2/3
0 0
(二)求 E[XY]
1 1
擬答： ∫∫x^2(y^2+1.5y)dxdy = ∫x^2dx ∫y^2+1.5y dy = 1/3 (13/12) = 13/36
0 0
請問是否可以這麼做?
--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 220.129.75.34
※ 文章網址: https://www.ptt.cc/bbs/Math/M.1449045164.A.A14.html
→
12/02 21:07, , 1F
12/02 21:07, 1F
→
12/02 21:07, , 2F
12/02 21:07, 2F
→
12/02 21:08, , 3F
12/02 21:08, 3F
→
12/02 21:49, , 4F
12/02 21:49, 4F
→
12/02 21:50, , 5F
12/02 21:50, 5F
→
12/02 21:51, , 6F
12/02 21:51, 6F
→
12/02 21:52, , 7F
12/02 21:52, 7F
→
12/02 21:53, , 8F
12/02 21:53, 8F
→
12/02 21:53, , 9F
12/02 21:53, 9F
→
12/02 22:12, , 10F
12/02 22:12, 10F
→
12/02 22:24, , 11F
12/02 22:24, 11F
→
12/02 22:26, , 12F
12/02 22:26, 12F
推
12/02 22:41, , 13F
12/02 22:41, 13F
討論串 (同標題文章)
