1 . 从一个有53名学生的班级中,随机抽取5人去参加活动,若采用系统抽样的方法抽取,则班长被抽中的概率为____________ .
您最近一年使用:0次
名校
2 . 下列四个命题
①样本方差反映的是所有样本数据与样本平均值的偏离程度;
②从含有
个个体的总体中抽取一个容量为
的样本,现采用系统抽样方法应先剔除
人,则每个个体被抽到的概率均为
;
③从总体中抽取的样本数据共有
个
,
个
,
个
,则总体的平均数
的估计值为
;
④某中学采用系统抽样方法,从该校高一年级全体
名学生中抽
名学生做牙齿健康检查,现将
名学生从
到
进行编号,已知从
这
个数中取得的学生编号是
,则初始在第
小组
中随机抽到的学生编号是
.
其中真命题的个数是_____ 个
①样本方差反映的是所有样本数据与样本平均值的偏离程度;
②从含有
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76e62bd2de8e4c51d4bb22c330058871.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0efba7147f5b9ced8bc4a72f0a9fb8af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd3304e23f3b0f9569c4140ca89b6498.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba8930e9a26a52a6b09740c1dddbd40e.png)
③从总体中抽取的样本数据共有
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c85481cd7e94130ef3aa05b4a39e79cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/888c0649b0504f4451ffc45d6405277c.png)
④某中学采用系统抽样方法,从该校高一年级全体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4f0e3992efedab109b99e6e172e6238.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e6f1af4b44b2e97e8f319bab4ae9010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4f0e3992efedab109b99e6e172e6238.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f23d07d9fb36737fc9b146e9f01cda6b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4f0e3992efedab109b99e6e172e6238.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1776f29d0681a32322d368731ebc4553.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c748e40ba21ac5063d3bccaa57ef278.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddba0756d6e5166122b61e269fcb0e88.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b26c2d5b30e784871aef7bf0b3e0a043.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18b38557a09f4a1ddbce816cf73a918.png)
其中真命题的个数是
您最近一年使用:0次