题目
题型:孝感模拟难度:来源:
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(1)求犬A能够入选的概率;
(2)规定:每有一只防暴犬入选,则相应的训练基地积3分,否则积0分.求该基地总积分的期望.
答案
P(A)=
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(2)解法一:记该基地总积分为ξ,则ξ的所有可能取值为:0,3,6,9,12.------(6分)
且P(ξ=0)=(1-
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P(ξ=3)=
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81 |
P(ξ=6)=
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P(ξ=9)=
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P(ξ=12)=(
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