After you answer the above question, here comes a related

來源: bearsback 於 2009-12-06 19:07:30 [] [博客] [舊帖] [給我悄悄話] 閱讀數 : (162 bytes)
本文內容已被 [ bearsback ] 在 2009-12-10 08:06:15 編輯過。如有問題，請報告版主或論壇管理刪除.

one:
each of the 100 people visits this forum with prob. 0.5. What is the standard deviation for the total number of times these people visit the forum?
ha

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• 我也想搞清楚：什麽是standard deviation? 我的書上都 -not.me- ♀ 給 not.me 發送悄悄話 not.me 的博客首頁 (54 bytes) () 12/06/2009 postreply 19:23:48

• standard deviation 很難。我一直沒搞懂。 -bearsback- ♂ 給 bearsback 發送悄悄話 bearsback 的博客首頁 (69 bytes) () 12/06/2009 postreply 20:16:32

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