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wenwen0727

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[求助] 有关概率的几个计算

求计算:
calculate the followings:
1. out of those who are convicted, the proporion of those who truly commit crimes is 90%. its is also known that the proportion of those go free even though they truly commit crimes is 10% and the proportion of those who has the verdict of innoience when they are really innocent is 80%, what is the condinent probalility that he/she is really guilty?

2.a city with a big polulation has 20% ill people. pick up 2 at local dishicts A and B incide the city with inhabitants 100 and 10000 respectively. compare the probability of all the inhabitants of A and B are healthy? using this comparison, do you think there is a particular reason why A is performing beHer than B in terms of people's health issue?

3. there are two bares A and B both of which are known to have 100 balls with unknown preportions of white and red balls. from A we you pick up 3 balls in which 2 balls are red. you do the same experiment for B with the result of 1 red ball. form this, can you inform that the proportion of red balls in both boxes are the same or can you   inform differently?
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