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英语翻译When doing blood testing for a viral infection,the proce

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英语翻译
When doing blood testing for a viral infection,the procedure can be made more efficient and less expensive by combining partial samples of different blood specimens.If samples from five people are combined and the mixture tests negative,we know that all five individual samples are negative.Find the probability of a positive result for five samples combined into one mixture,assuming the probability of an individual blood sample testing positive for the virus is 0.07.
1 - 0.07 = 0.93 (probability of an individual blood sample testing negative for the virus)
0.93 x 0.93 x 0.93 x 0.93 x 0.93 = 0.6957 (probability of all 5 individual samples are negative)
1 - 0.6957 = 0.3043 (as long as 1 individual sample is positive,all 5 will be positive)
这题其实是很基础的统计学应用题.首先要懂得题意.如果五个取样混合都是阴性,那么 我们知道五个样本单独都是阴性.换句话说,只要五个样本单独有一个是阳性,那么五个取样混合就会是阳性.所以要解这题,首先要找出五个人全部都是阴性的几率,然后用100%减去全部阴性的几率,就得到其中任何一个或几个是阳性的几率了.