福建英语周报2022答案

17.【学科素养】试题以实际问题为背景,引导考生在实际情境中从数学的视角分析问题,知道如何建立数学模型解决问题,体现了理性思维、数学应用、数学探索学科素养【解题思路】(1)利用参考公式、参考数据及已知数据求出相关系数r,再进行判断;(2)先由62(x-x)(y-y)求出b,再由a=y-bx求x出a,即得回归方程解:(1)由图中数据和参考数据得x=3,y=3.592,∑(x1-x)yi-y(1分)点(x-)(y-5)=2y.-5=59.06-3×3.592×5=5.18(3分)所以5.18≈0.9963.162×1.644(5分)因为0.996趋近于1,说明y与x的线性相关程度相当强,从而可以用线性回归模型拟合y与x的关系.(在线性回归模型中,相关系数r越趋近于1两变量正相关性越强)(6分)(2)由(1)得B、(x-x)(y2-y)5.1810=0.518,(8分)a=y-bx=3.592-0.518×3=2.038,(10分)所以y关于x的回归方程为y=0.518x+2.038(12分)【解题关键】用最小二乘法求回归方程,关键在于正确求出a,b,由于求a,b时的计算量较大,计算应认真仔细

书面表达One possible version:Dear Jack,I am happy to know that you are to spend some time in China. I recommend you stay in Beijing, the capital andcultural center of China.First of all, there are a lot of museums where precious relics of historical interest are waiting for you toexplore. Besides, the exceptional Peking Opera performances there are also what you can t miss. And the city isalso best known for its abundance of ancient buildings, which are still well preserved.I hope that you will have a good time in China.Yours sincerely,Li Hua

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