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【简答题】
设随机变量X的概率密度为，求数学期望E(X)和方差D(X)。 设随机变量X的概率密度为 f(x)=(1/2)*e^(-|x|) ，求数学期望E(X)和方差D(X)。
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举一反三
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B.
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C.
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D.
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B.
CAME1s评级包括五大类要素评级和一个综合评级
C.
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D.
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【多选题】下列关于CAME1S评级的说法，正确的有（ ）。
A.
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B.
CAME1S评级包括五大类要素评级和一个综合评级
C.
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D.
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E.
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转向战略
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紧缩与集中战略
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稳定战略
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