推 starsky822 :謝謝a大，至於問題2我已解決了，感謝!!! 10/24 08:15
※ 引述《starsky822 (豆漿)》之銘言：
老師要求解出上課時的習題，但不是很了解@@"
因想了半天想不出來，所以想來尋求各位幫忙!!!
問題1
In a particular community, 70% of the voters are Democrats, and 30% are
Republicans. Thirty percent of the Republican voters and 60% of the
Democratic voters favor the incumbent. What is the probability that a
randomly selected voter from this community is a Republican who favors the
incumbent?
70% Dem... 30% Rep...
60% 30% favor th incumbent
是 rep... 且 favor the incumbent =>30%*30%=9%
問題2
The frequency of twin births has been increasing in recent years so that in
2000 about 3% of all births were twins. Twins may be either identical or
fraternal. The probability of a birth being that of identical twins has
remained fairly constant at 0.4%. What proportion of twin births is identical?
看不懂意思O_Q
在此求助各位的幫忙，先謝謝各位了!!!
謝謝!!!
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※ 編輯: a181w 來自: 114.37.73.176 (10/24 01:29)