作者smallwhite28 (给我你的爱)
看板Statistics
标题[问题] 机率问题
时间Wed Mar 19 10:02:32 2008
元智下礼拜就要考试了
最近做了考古题，因为没有答案，所以很多都不确定
可以请各位帮我解一下以下几题 谢谢!!!
1. A person's wallet is missing and it is presumed that
is was equally likely to have been forgot in any of
three possible places .Let Wi denote the probability
the wallet will be found upon a search of the ith place
when the wallet is in the place, i=1.2.3 . Let F be the
event that a search of place 1 is unsuccessful; and let
Ri , i=1.2.3 ,be the event that the wallet is in the
place i .
(a)What is the probability of R2
(b)What is the probability of F,given that R2 has occurred
(c)What is the probability of F
(d)What is the probability of R1,given that F has occurred
2. Let X have a continuous distribution with density e^(-x)
for x > 0 and 0 for x < = 0. Let Y=[X] be the integer part
of X ,and let Z be in integer nearest to X. Find
(a)The probability mass function of Y
(b)The probability mass function of Z
(c)P(Y=Z)
(d)P(Y=2|Z=3)
(e)P(Z=2|Y=3)
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 140.127.200.50