作者check (且可)
看板Grad-ProbAsk
标题[问题] 一题机率的问题？
时间Mon Mar 23 23:20:20 2009
从高中毕业後就没有读相关机率的科目了
想不到中山资管没考统计的那组，在某些考科也有一些机率的问题
97中山资管-资料结构
Suppose you have three coins, A, B,and C.
A is a fair coin, B has 3/4 probability of coming up with head,
and C always comes up with head.
(A)If you choose B and toss it three times,what is the probability
that you get three heads?
(B)If you randomly choose a coin, toss it three times,
and get three heads,what is the probability that the coin you
chose is C?
请问(A)是(3/4)*(3/4)*(3/4)吗？
(B)就不知道要怎麽解了？
麻烦帮忙一下，非常感谢。
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1F：推 BF3716:(A) 算法是正确的 03/24 03:20
2F：→ BF3716:(B) 有1/3会抽到A铜板，此时连三正面=(0.5)*(0.5)*(0.5) 03/24 03:23
3F：→ BF3716: 有1/3会抽到B铜板，此时连三正面=(0.75)*(0.75)*(0.75) 03/24 03:23
4F：→ BF3716: 有1/3会抽到C铜板，此时连三正面=(1)*(1)*(1) 03/24 03:24
5F：→ BF3716:总共机率为 (1/3)*(1/8)+(1/3)*(27/64)+(1/3)*1 03/24 03:25
6F：推 BF3716:抽到C铜板的机率为 (1/3)*1*1*1/总共机率 03/24 03:28
7F：推 zegolas:谢谢BF大的解答。 03/24 08:14
8F：→ check:非常感谢BF大的回应，祝您考上理想的学校。 03/24 08:17