1 . 某电脑公司有5名产品推销员,其工作年限与年推销金额的数据如表:
求年推销金额y关于工作年限x的线性回归方程;
判断变量x与y之间是正相关还是负相关;
若第6名推销员的工作年限是11年,试估计他的年推销金额.
【参考数据
,
,
参考公式:线性回归方程
中
,
,其中
为样本平均数】
推销员编号 | 1 | 2 | 3 | 4 | 5 |
工作年限 | 3 | 5 | 6 | 7 | 9 |
推销金额 | 2 | 3 | 3 | 4 | 5 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9bf6c84731e5e1bd335ecfc2d36c3d81.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f53190d6ead827a6338b9de847aeaf1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f62295c36d2e2174908c2bec0eb5b30f.png)
【参考数据
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7847ff12ddfc157fedae237f30916c91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32e6791adb181e0a1d5387fc6222c64a.png)
参考公式:线性回归方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1db6103cb0f1d2bd6b19235d53ee7e98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad33923664ac6f63ea198e9b3ee8b3c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a58291bd91befe1061530246da983727.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed787b806df05c8928498d76cf9aed37.png)
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2 . 如图是两个变量x和y的样本数据散点图,由图可知x和y
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/5/d7ad3cbe-5672-4fb5-bf54-9a406642bb61.png?resizew=156)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/5/d7ad3cbe-5672-4fb5-bf54-9a406642bb61.png?resizew=156)
A.不相关 | B.成函数关系 |
C.负相关 | D.正相关 |
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解题方法
3 . 下列命题中是真命题的有:___________ (只填序号).
①根据最小二乘法由一组样本点
(其中
),求得的回归方程是
,若回归直线
的斜率
,则变量
与
正相关;
②“
”是直线
与圆
相切的充要条件;
③若直线
的倾斜角是
,则直线
的斜率
;
④已知双曲线
以及点
,则以
为中点的弦所在直线的斜率为
.
①根据最小二乘法由一组样本点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef046c85a536174bec951a53d9f60b33.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6358f2068c91f345ab28cbdd0ba29fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/929ef3bed0a4bdd22f39e036506dc481.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/929ef3bed0a4bdd22f39e036506dc481.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e7b0d3d6bc11e8e6c70bf9de036fb8e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
②“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a882037b9ce104ecc496e0f31a139361.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7cbd884c1e1fc8e5f3f3226cd7659be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d61985901c2bc698d72ac88f4e1eb65.png)
③若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e41f9455d9fbc3a04ef8cec22dae9d4.png)
④已知双曲线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c465114dc2665d74246240b1d4d26ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/908c9588178c02002157ad54eb440a56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81fb134b2b48acc99213fff6ccfee65f.png)
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名校
4 . 下面对相关系数
描述正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11bc05f41215f9894e11d1df0465751a.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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