A drawer contains 10 batteries, 3 of which are defective. Three batteries are drawn without replacement. Find P(x=1) where X represents the number of defective batteries and E(X).
I know it is an hypergeometric distribution, but don't know how to set it up?
Hypergeometric Distribution?
2017-05-11 4:20 am
回答 (1)
2017-05-11 6:23 pm
✔ 最佳答案
P(x) = C(3,x) * C( 7 , 3-x ) / C(10,3)P(1)
= C(3,1) * C(7,2) / C(10,3)
= 3*21 / 120
= 21/40
= 0.525 ..... Ans
E(X)
= n * p
= 3 * 3/10
= 0.9 ..... Ans
收錄日期: 2021-05-02 14:11:48
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