作者chrisjon (研究布丁狗)
看板Statistics
标题[问题] 一些考古的题目意思
时间Sat Jan 20 21:55:09 2007
1.93清大统计
Let X1,…,Xn be iid sample observations from a population with cdf F(x)
where -∞<X<∞.Define a random variable
W ≡ the nmber of X1,…,Xn ≦ c
where c is a given constant
(a) Find the distribution of W
老师给的答案是 W～B(n,p=F(c))
可是我还是看不太懂题目到底在讲什麽
2.93彰师数学
A point is selected at random and uniformly from the region
R = {(x,y)│|x|+|y|≦1}
(i) find the probability density function of
the x-coordinate of a selected point.
(ii) find the probability density function of the sum of
x-coordinate and y-coordinate of a selected point.
selected point是要选择什麽point??
3.93成大统计
Which of the following statement(s) is/are true?
(1).The distribution function of a negative binomial distribution is
a step function with jumps at positive integers and zero.
(2)
(3)A distribution function has to be right-continuous
right-continuous 是???
5.93成大统计
Let Xn~Fn,1，what is your best approximated value of c such that
P(Xn>c) = 0.95 when n → ∞?
F(1,n)是～T^2，F(n,1)是??
6.93成大统计
If X and Y are independent standard normal random variables, what is the
distribution of Y/X , the ratio of Y to X
什麽是 Y to X的ratio??
7.94清大统p
Let X1,X2, be a sequence of i.i.d random Variables with mean μ and
variable σ^2 and let N, independent of X's, be a binomial random variable
with parameters(n,p)
The random sum,denoted
S(N),is given by S(N)=ΣX1,(S(0) = 0) Find
S(N)的N是下标小字体，S(0)也是一样，下标小零
这题是完全不懂~.~
请各位先进不吝指教
谢谢
--
棒球队棒球队的坚强阵容
谁在一垒，什麽在二垒，三垒我不知道
今天当补手，明天在投球
为什麽在左外野，因为他在中外野
我不管啦是游击手，天啊他是裁判
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 125.229.72.152
1F：推 ajuoiuu:right-continuous <=右连续吧@@" 01/20 23:51
2F：推 ajuoiuu:If X is independent from Y, then the joint range of X 01/20 23:53
3F：→ ajuoiuu:and Y has to be a rectangular 意思就是问联合分配的 01/20 23:54
4F：→ ajuoiuu:X和Y的range 是否为正交型@@" 01/20 23:55
5F：推 ajuoiuu:上面的回答可能不知道有没有错@@" 01/20 23:58
6F：推 koming:the ratio of Y to X====>Y/X吧纯粹叙述 01/21 00:01
7F：推 koming:清大那题~~E(S_N)=E(N)E(X)=(np)(μ) 01/21 00:06
8F：推 chrisjon:正交不是垂直?或者是什麽?? 01/21 03:29
9F：推 ajuoiuu:X和Y的range 是否有关系啦@@" 01/21 08:18
10F：→ ajuoiuu:就是如果X和Y的range会不会互相影响@@" 01/21 08:18
11F：→ ajuoiuu:ex: 0<x<1 , 0<y<1 <= 不会影响 0<x<y ,0<y<1 <=会影响 01/21 08:18
12F：推 koming:答案应该是YES,X独立Y->X和Yrange to be a rectangular 01/21 10:17
13F：推 TOOYA:这篇是替各位考生建立自信的吗?? 我感受到了 谢谢!!<_ _> 01/22 13:54
14F：推 chrisjon:你在让我失去自信的吗orz 01/22 14:04
※ 编辑: chrisjon 来自: 125.229.73.223 (01/22 14:56)
15F：推 TOOYA:噗 我开玩笑的啦^^ 还没完全看懂题目 有几个地方有点模糊XD 01/23 13:50