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单选题 若两个独立的随机变量
和
的方差分别为4和2,则
的方差为( )
学科：概率论与数理统计（仅用于完成作业及单元自测线上部分）
时间：2023-12-21 01:42:20
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题目1单选题
已知随机变量<img src="https://tihai-oss-cloud.itihey.com/img/4f30769d86d4432da63add60f417d8b4.png"> ,则<img src="https://tihai-oss-cloud.itihey.com/img/4deaa963b863b501a8b8f546ec24fe6c.png">( )A. 9B. 24C. 18D. 12
题目2单选题
随机变量<img src="https://tihai-oss-cloud.itihey.com/img/e22a13f7edcffe98b7a922d3fe5be3b8.png">和<img src="https://tihai-oss-cloud.itihey.com/img/7390c6742b283db67f12827b93bce7d7.png">满足<img src="https://tihai-oss-cloud.itihey.com/img/6e10b8bd80c0c2f0ca87e1effded7d41.png"> ,则下列选项正确的是( )A. <img src="https://tihai-oss-cloud.itihey.com/img/e40e915f4069bbc64ced0ba6e30aaa22.png">B. <img src="https://tihai-oss-cloud.itihey.com/img/e22a13f7edcffe98b7a922d3fe5be3b8.png">和<img src="https://tihai-oss-cloud.itihey.com/img/7390c6742b283db67f12827b93bce7d7.png">相互独立C. <img src="https://tihai-oss-cloud.itihey.com/img/e22a13f7edcffe98b7a922d3fe5be3b8.png">和<img src="https://tihai-oss-cloud.itihey.com/img/7390c6742b283db67f12827b93bce7d7.png">相关D. <img src="https://tihai-oss-cloud.itihey.com/img/ff70813021d2931b76c96372e2bf6ed3.png">
题目3单选题
已知<img src="https://tihai-oss-cloud.itihey.com/img/c9e2e9d28a22d5936e6ab1ac2790812b.png">( )A. 5B. 无法计算C. 30D. 6
题目4单选题
随机变量<img src="https://tihai-oss-cloud.itihey.com/img/e22a13f7edcffe98b7a922d3fe5be3b8.png">和<img src="https://tihai-oss-cloud.itihey.com/img/7390c6742b283db67f12827b93bce7d7.png">满足<img src="https://tihai-oss-cloud.itihey.com/img/c1476cdaa2cfabcd8b083b75445fc833.png"> ,则( )A. <img src="https://tihai-oss-cloud.itihey.com/img/e22a13f7edcffe98b7a922d3fe5be3b8.png">和<img src="https://tihai-oss-cloud.itihey.com/img/7390c6742b283db67f12827b93bce7d7.png">不相互独立B. <img src="https://tihai-oss-cloud.itihey.com/img/638a41f6222130cdb187f04ef8f0c00c.png">C. <img src="https://tihai-oss-cloud.itihey.com/img/e22a13f7edcffe98b7a922d3fe5be3b8.png">和<img src="https://tihai-oss-cloud.itihey.com/img/7390c6742b283db67f12827b93bce7d7.png">线性相关D. <img src="https://tihai-oss-cloud.itihey.com/img/a716d9cbcd86f45a774e8f0dba89efb5.png">
题目5单选题
若两个独立的随机变量<img src="https://tihai-oss-cloud.itihey.com/img/e22a13f7edcffe98b7a922d3fe5be3b8.png">和<img src="https://tihai-oss-cloud.itihey.com/img/7390c6742b283db67f12827b93bce7d7.png">的方差分别为4和2,则<img src="https://tihai-oss-cloud.itihey.com/img/3a667d5f39dd847b4a21239fbc61365e.png"> 的方差为( )A. 44B. 8C. 24D. 32
题目6单选题
已知随机变量<img src="https://tihai-oss-cloud.itihey.com/img/4f30769d86d4432da63add60f417d8b4.png">,则<img src="https://tihai-oss-cloud.itihey.com/img/e5470c8c4af71725c154241e9237765e.png">( )A. 78B. 77C. 76D. 84
题目7单选题
设随机变量<img src="https://tihai-oss-cloud.itihey.com/img/22436ac64c605aa703c61e4b57a4a4ae.png">的分布律如下,<img src="https://tihai-oss-cloud.itihey.com/img/130970be36723c690883f7b784f65038.webp">且<img src="https://tihai-oss-cloud.itihey.com/img/1dcf42151bcbeb7d5c13f65e32a61316.png">,则<img src="https://tihai-oss-cloud.itihey.com/img/99648cf98bbd94bd73811f380479eb89.png"> 值为()A. 0.1,0.2B. 0.2,0.3C. 0.4,0.1D. 0.3,0.2
题目8单选题
设随机变量<img src="https://tihai-oss-cloud.itihey.com/img/e22a13f7edcffe98b7a922d3fe5be3b8.png">的分布律如下,<img src="https://tihai-oss-cloud.itihey.com/img/4eb34b74f1e534b7377e792be6e0c5fe.webp"> 则<img src="https://tihai-oss-cloud.itihey.com/img/4deaa963b863b501a8b8f546ec24fe6c.png">( )A. 2.4B. 0C. 4.4D. 2
题目9单选题
设随机变量X和Y的联合概率分布如下,则X和Y的协方差<img src="https://tihai-oss-cloud.itihey.com/img/7fc11ac588740f014ded9bb5b19f09f2.png">( )A. 1B. 2C. 3D. 0
题目10单选题
已知随机变量<img src="https://tihai-oss-cloud.itihey.com/img/e22a13f7edcffe98b7a922d3fe5be3b8.png">服从二项分布,且<img src="https://tihai-oss-cloud.itihey.com/img/190173e782a86480035ae7ac6533117d.png">,则二项分布的参数<img src="https://tihai-oss-cloud.itihey.com/img/eb5c03b05bc701167ac2019d11ad995e.png">的值为( )A. n=8,p=0.3B. n=6,p=0.4C. n=4,p=0.6D. n=24,p=0.1
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