作者zptdaniel (人生啊..)
看板Statistics
標題[問題] 兩題 Distribution of sampling Statistics的問題
時間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.
這兩題不會寫..我承認這是學校的作業@@
雖然已經過了繳交期限..不過還是想完成
想請板上的高手教我,感謝!
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1F：→ yhliu:1. 利用中央極限定理 (常態近似). 又: 個別捨入誤差應是 01/11 09:21
2F：→ yhliu: -0.5～0.5 間之 uniform, 而非 -5～5. 01/11 09:21
3F：→ yhliu:2. 也是應用中央極限定理. 01/11 09:22
4F：→ zptdaniel:謝謝,我再試試! 01/11 15:37