1 . 下表为某宝网站店主统计的月促销费用(万元)与月净利润(万元)数据表:
(1)根据数据绘制的散点图能够看出可用线性回归模型拟合
与
的关系,请用相关系数
加以说明;(系数精确到
);
(2)建立
关于
的回归方程
(系数精确到
);如果该店主想月净利润超6万元,预测理论上至少需要投入促销费用多少万元(结果精确到
).
参考数据:
,
,
,
,
,其中
分别为月促销费用和月净利润,
.
参考公式:(1)样本
的相关系数
.
(2)对于一组数据
,其回归方程
的斜率和截距的最小二乘估计分别为
,
.
促销费用 | 2 | 3 | 6 | 10 | 13 | 21 | 15 | 18 |
月净利润 | 1 | 1 | 2 | 3 | 3.5 | 5 | 4 | 4.5 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11bc05f41215f9894e11d1df0465751a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e2c4d12b3a705daab723ab243b6cc88.png)
(2)建立
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1db6103cb0f1d2bd6b19235d53ee7e98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e2c4d12b3a705daab723ab243b6cc88.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e2c4d12b3a705daab723ab243b6cc88.png)
参考数据:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f08f680d8d531bb39e931929b109e46.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98ff3b8cfd7d70c0901975e1238d9448.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfdc80763b3f6a4f6e2b9f14fbe5f19e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4b2044aa6586e60e96fea47ece88ac5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16fa7b1e1bf9a266025f364d0fc0d708.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19495cd010ca937c53d602ea8c604851.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d261c54950555547a93fb49d9780eaf.png)
参考公式:(1)样本
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33f9d80fec2bd044e94279526a2b3246.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3dec835d016f15edebf89ece561307f.png)
(2)对于一组数据
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/330f3329ed973a622638cb613ef5cfbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1db6103cb0f1d2bd6b19235d53ee7e98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/686cf982bb021a8cd878a0fd4b198db1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8112f4d3ab5f8ec8405fe32fd181ce32.png)
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