[問題] 兩題機率
1. Let the number of trees that grow in a region of area A have a Possion
distribution with expectation λA .Find the expected value of the distance
from a certain tree to its nearest neighbor?
2. Let X and Y be two random variable with joint pdf f(x,y).If E[Y|X=x] is
a linear function of x, that is , if E[Y|X=x]=a+bx,for some a,b. then
E[Y|X=x]= Uy + p*(SigmaY/SigmaX)*(x-Ux).
Uy,Ux分別表y,x的平均
SigmaY SigmaX 表 y,x的標準差
p表相關係數
sorry...因為這些符號不會打....
我只知道第二題符合二為高斯
但是為什麼卻不清楚
3. Let X and be independent random variables each geometrically distributed
with parameter p ,i.e P[X=x]=p(1-p)^x ,x=0,1,2...
Please find the distribution of min(X,Y)
4. Let X denote the life length of a certain type of electronic componect.
These components frequently fail immediately upon insertion into a system.
It has been observed that the probability of immediate failure is 1/3.
If a component does not fail immediately, its life-length distribution
has exponential f(x)=e^(-x) , x>0
Find the distribution function for X and evaluate P(X>10)
麻煩各位大大解答一下
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 140.112.115.224
※ 編輯: maxmilian 來自: 203.67.89.8 (11/23 01:29)