作者BaiYe (摆耶)
看板NTU-Exam
标题[试题] 99下 陈鹏文 机率导论 第四次小考
时间Fri Jun 10 16:18:02 2011
课程名称︰机率导论
课程性质︰必修
课程教师︰陈鹏文
开课学院：理学院
开课系所︰数学系
考试日期（年月日）︰2011/06/02
考试时限（分钟）：30分钟
是否需发放奖励金：是
试题 :
1. Suppose that the joint density of Ｘ and Ｙ is given by
exp(-x/y) exp(-y)
f(x,y) = ------------------- , 0 < x < ∞ , 0 < y < ∞ .
y
Compute E[Ｘ|Ｙ=y].
2. Let Ｘ be the number of 1's and Ｙ the number of 2's that occur in n rolls
of a fair die.
Compute the correlation ρ(Ｘ,Ｙ).
3. A group of 16 people consisting of 8 men and 8 women is randomly arranged
into 8 pairs of 2 each.
Compute the expectation and variance of the number of pairs thaht consist
of a man and a woman.
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 140.112.248.245