[問題] 請問交大機率問題
是這樣的 這題是交大98統研機率論第一題
因為同一個老師解了不同版本(成大93年有考過)
所以想請教各位 拜託了....
題目↓↓
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?
其實是我不太懂他要求什麼>"<
版本一：題給P(判定嫌犯有罪)=0.65
所求=P(左嫌│有罪)=(0.23*0.85)/0.65=0.301
版本二： 0.85 / 罪 0.23
左 0.15 \ 無罪
a /
1-a \ b / 罪
右 1-b \ 無罪
a = 0.23/0.85 = 0.27
b = (0.65-0.73)/0.73= 0.58
所求 = 0.27*0.85+0.73*0.58 = 0.6525
請問哪一個才是對的??
還是兩個都不對呀?? 因為同學和學長都說好像都不對 卻解不出來>"<
拜託請求好心人幫我解答^^
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 61.64.114.65
※ 編輯: ivy750910 來自: 61.64.114.65 (01/20 23:30)
→
01/21 09:46, , 1F
01/21 09:46, 1F
討論串 (同標題文章)