同月同日生概率

究竟你是想問「在n人當中至少兩人於同月同日出生的概率」還是想問「在n人當中至少兩人於同月同日慶祝生日的概率」？

2008-11-17 23:41:24 補充：
First consider the case in leap year (閏年):

In leap year, the persons celebrate their birthday at the same day is equivalent to the persons born on the same day. So we can use the method in http://www.efgh.com/math/birthday.htm.

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By using the information in http://hk.knowledge.yahoo.com/question/question?qid=7008051902660,


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參考資料：
method from隨http://zh.wikipedia.org/w/index.php?title=%E7%94%9F%E6%97%A5%E6%82%96%E8%AB%96&variant=zh-hk附送的網站http://www.efgh.com/math/birthday.htm + notation referenced from隨http://zh.wikipedia.org/w/index.php?title=%E7%94%9F%E6%97%A5%E6%82%96%E8%AB%96&variant=zh-hk附送的網站http://mathworld.wolfram.com/BirthdayProblem.html + my wisdom of maths + http://en.wikipedia.org/wiki/Gamma_function

根據
http://hk.knowledge.yahoo.com/question/question?qid=7008051902660
http://hk.knowledge.yahoo.com/question/question?qid=7008102200187

現時有 n 人, 則當中至少兩人於同月同日生的機會為多少?(n是任何不包括1的自然數)


我認為是:
58468191/146097^n x 1/(400 x 146097^n) x [364 x 400^n 1 303 x 497^n 97 x (400^n 97^n)]



如錯了,請指教。

doraemonpaul 君, 感謝你的提示:
應該係問「在n人當中至少兩人於同月同日慶祝生日的概率」, 即跟返在你之前發問的兩題當中的規則.