对具有线性相关关系的变量x和y，测得5组数据如下表所示
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∵
=. x
=5，2+4+5+6+8 5
=. y
=50，∴这组数据的样本中心点是（5，50）30+40+60+50+70 5
把样本中心点代入回归直线方程
=6.5̂ y
+a，求得a=17.5，∴回归直线的方程为̂ x
=6.5̂ y
+17.5，̂ x
故答案为
=6.5̂ y
+17.5̂ x
| 从方框中选出适当的句子补全对话，其中有两项是多余的。 | |
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| A: Hi, Jack. You were not at school yesterday. (1) B: Oh, I had a headache and I had to ask for a sick leave. A: Sorry to hear that. (2) B: Yes, my mother took me to the hospital. The doctor looked me over and said I had caught a cold. A: (3) B: Yes, a little. The doctor told me to take these pills three times a day and drink more water. A: (4) B: Yes, much better. A: (5) B: I will. Thank you. |