题目
题型:台州一模难度:来源:
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(1)设ξ为攻关期满时获奖的攻关小组数,求ξ的分布列及数学期望Eξ;
(2)设η为攻关期满时获奖的攻关小组数与没有获奖的攻关小组数之差的平方,记“函数f(x)=|η-
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答案
P(ξ=0)=P(
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B |
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P(ξ=1)=P(
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B |
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3 |
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P(ξ=2)=P(A•B)=
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∴ξ的分布列为:
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1 |
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B |
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3 |
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1 |
12 |
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B |
2 |
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3 |
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2 |
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3 |
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12 |
2 |
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3 |
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2 |