[問題] 一題機率的問題

看板Grad-ProbAsk作者 (且可)時間16年前 (2009/03/23 23:20), 編輯推噓3(3推 0噓 5→)
留言8則, 3人參與, 最新討論串1/1
從高中畢業後就沒有讀相關機率的科目了 想不到中山資管沒考統計的那組，在某些考科也有一些機率的問題 97中山資管-資料結構 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? 請問(A)是(3/4)*(3/4)*(3/4)嗎？ (B)就不知道要怎麼解了？ 麻煩幫忙一下，非常感謝。 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 218.170.109.62
推
03/24 03:20, , 1F
(A) 算法是正確的
03/24 03:20, 1F
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03/24 03:23, , 2F
(B) 有1/3會抽到A銅板，此時連三正面=(0.5)*(0.5)*(0.5)
03/24 03:23, 2F
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03/24 03:23, , 3F
有1/3會抽到B銅板，此時連三正面=(0.75)*(0.75)*(0.75)
03/24 03:23, 3F
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03/24 03:24, , 4F
有1/3會抽到C銅板，此時連三正面=(1)*(1)*(1)
03/24 03:24, 4F
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03/24 03:25, , 5F
總共機率為 (1/3)*(1/8)+(1/3)*(27/64)+(1/3)*1
03/24 03:25, 5F
推
03/24 03:28, , 6F
抽到C銅板的機率為 (1/3)*1*1*1/總共機率
03/24 03:28, 6F
推
03/24 08:14, , 7F
謝謝BF大的解答。
03/24 08:14, 7F
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03/24 08:17, , 8F
非常感謝BF大的回應，祝您考上理想的學校。
03/24 08:17, 8F
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