※ 引述《qazpoi753 (草間雨)》之銘言:
: 現在確定有65%的把握確定這個嫌犯有犯案。在審辦的過程中,一個證人出面指證
: 嫌犯有85%的機會是左撇子。假設有23%的人口數都是左撇子,而嫌犯也是左撇子
: 請問在獲得證人的資訊後,嫌犯犯案的機率變成多少?
: 因為怕自己翻譯的不對,所以題目原文也貼上來
: A judge is 65% sure that a suspect has committed a crime. During the course of
: the trial a witness convinces the judge that there is an 85% chance that the
: criminal is left-handed. If 23% of the population is left-handed and the
: suspect is also left-handed, with this new information, how certain should
: the judge be of the guilt of the suspect?
: 請各位板友幫我解決這個問題
: 謝謝
很久沒碰機率了 我個人覺得是這樣
犯案的機率可能是
犯人是左撇子 且 被指證為左撇子 且他有犯罪
或是
犯人是右撇子 且 被指正為右撇子 且有犯罪
也就是 23% * 85% *65% + 77% * 15% * 65%
個人淺見
鞭小力點~~~`
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