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盒中有12只晶体管,其中有2只次品,10只正品,现从盒中任取3只,求取出的3只所含次品数X的分布列.
分类:
概率论与数理统计(经管类)(04183)
发表:2024年09月12日 09时09分29秒
作者:
admin
阅读:
(12)
盒中有12只晶体管,其中有2只次品,10只正品,现从盒中任取3只,求取出的3只所含次品数X的分布列.
【正确答案】:从12只晶体管中任取3只,次品数X的可能值分别为0,1,2.且有 P(X=0)=C
2
10
/C
3
12
=6/11,P(X=1)=(C
1
2
C
2
10
)/C
3
12
=9/22, P(X=2)=(C
2
2
•C
1
10
)/C
3
12
=1/12 所以取出3只所含次品数X的分布列为: X 0 1 2 P 6/11 9/22 1/22
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