作者zptdaniel (人生啊..)
看板Statistics
标题[问题] 两题 Distribution of sampling Statistics的问题
时间Sat Jan 10 23:43:02 2009
1.
Fifty numbers are rounded off to the nearest integer and then
summed. If the individual roundoff errors are uniformly distributed
between -5 and 5, what is the approximate probability that the resultant
sum differs from the exact sum by more than 3?
2.
A six-sided die, in which each side is equally likely to appear,
is repeatedly rolled until the total of all rolls exceeds 400.
Approximate the probability that this willrequire more than 140 rolls.
这两题不会写..我承认这是学校的作业@@
虽然已经过了缴交期限..不过还是想完成
想请板上的高手教我,感谢!
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 118.233.35.156
1F：→ yhliu:1. 利用中央极限定理 (常态近似). 又: 个别舍入误差应是 01/11 09:21
2F：→ yhliu: -0.5～0.5 间之 uniform, 而非 -5～5. 01/11 09:21
3F：→ yhliu:2. 也是应用中央极限定理. 01/11 09:22
4F：→ zptdaniel:谢谢,我再试试! 01/11 15:37