如果是跟统计软体有关请重发文章 如果跟论文有关也烦请您重发文章 文章类别是为了帮助大家搜寻资料与解答，造成不便之处请见谅 老师要求解出上课时的习题，但又不是很了解@@" 问题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? 问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? 在此求助各位的帮忙，先谢谢各位了!!! 感谢!!! --

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