10-11高二下·辽宁·期中
1 . 当
时,正态曲线为
,我们称其为标准正态曲线,且定义
,由此得到
________. .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f771fb9aa04e6a74b0e8634381cbab8b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/689d79546eb6533b08de3bc5ec98bcfe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fcbb0f3e5f7eceb5fb4bbe4667a3e59.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/728272ac69a5ae4558c58883be3f9141.png)
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10-11高二下·广东中山·期中
解题方法
2 . 某班有
名学生,一次考试的成绩
服从正态分布
. 已知
,估计该班数学成绩在
分以上的人数为______________.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e6f1af4b44b2e97e8f319bab4ae9010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/910b11390cd78f7dcb0af4634c2be4fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61674d66e5a3662843b21ab5182f903f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5868b58e16b71d60f09be3b52a6d76e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88ce87642d4f11148b5d8e65018431b5.png)
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3 . 已知随机变量
服从正态分布
,且
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c92278194f93b54876e6b319995f5a37.png)
![](https://img.xkw.com/dksih/QBM/2016/9/13/1573019206893568/1573019212627968/STEM/b3db1e5ef6094d9283a5a3504dd2f293.png?resizew=56)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3b57b3ad90d3a86b846515f871b221c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b76feef88189d436028d6477eb463bf.png)
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