问题如下:
Assume that the number of faulty vehicles is subject to the Possion distribution. And assume that 5% of the cars coming to the assembly line are faulty. Then randomly select 5 cars in the assembly line, and what is the probability that one of them is faulty?
选项:
A. 0.195
B. 0.235.
C. 0.181.
D. 0.179.
解释:
A is correct.
考点:Poisson Distribution
解析:根据Poisson分布的性质,λ=np=5*0.05=0.25
n不应该是总体个数吗(整个生产线的产量),如果选择n=5,np=5*0.05,若选择n是全部生产线的产量,比如1万,那np=500,两个拉姆达不一样,所以应该怎么理解n呢?