[img=580x46]1802e166884d776.png[/img]Then the deviation ratio is
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举一反三
- 1802e165fa6fc66.pngThen the deviation ratio is
- 1803a28eb384082.pngThen the deviation ratio is
- The likelihood ratio under [img=22x22]180300d4f5e5b87.png[/img] and [img=63x22]180300d4feef176.png[/img] is always between 0 and 1.
- 设投掷1颗骰子的点数为X,则( ) 未知类型：{'options': ['E(X)=3.5,D(X)= [img=29x21]17e43c3db9dc21b.png[/img]', ' E(X)=3.5, D(X)= [img=22x41]17e43c3dc2146ee.png[/img]', ' E(X)=3.5,D(X)=3.5', ' E(X)=3.5,D(X)=[img=22x41]17e43c3dcacf7d1.png[/img]'], 'type': 102}
- The slenderness ratio is [img=30x25]1803a0f79d25495.png[/img], where [img=9x14]1803a0f7a75d311.png[/img] is the ( ) radius of gyration of the cross section. Buckling will occur about the axis where this ratio gives the ( ) value. A: smallest, greatest B: smallest, smallest C: largest, greatest D: smallest, any
内容
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设随机变量 X ~ e([img=11x19]1803bbe33f2dc36.png[/img])，则 D(X )= [img=18x43]1803bbe34777894.png[/img].
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已知随机变量X的分布函数为[img=136x49]1803b69024c8270.png[/img] ，则X的均值和方差分别为 A: E(X)=2, D(X)=4 B: E(X)=4, D(x)=2 C: [img=162x43]1803b6902cd8bfb.png[/img] D: [img=162x43]1803b69034d9ffd.png[/img]
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设X为随机变量，若数学期望E(X)存在，则数学期望E(E(X))=__________。 A: E(X) B: 0 C: [img=51x27]18038f919d83a08.png[/img] D: [img=63x27]18038f91a6f0476.png[/img]
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已知随机变量X的分布列为[img=214x88]17e43c3ddb83914.png[/img],若E(X)=[img=21x41]17e43c3de3d0135.png[/img],则,D(X)=( ) 未知类型：{'options': ['', ' [img=24x41]17e43c3df5472ec.png[/img]', ' [img=22x41]17e43c3dfda6df0.png[/img]', ' [img=22x41]17e43c3e066e214.png[/img]'], 'type': 102}
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设非负随机变量X满足D(X)=E([img=24x22]18038fe450d4248.png[/img]-2EX-3)，则 E(X)=( ).