x={3,5,6,7,9},y={2,3,3,4,5} 求线性回归方程

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x={3,5,6,7,9},y={2,3,3,4,5} 求线性回归方程

x={3,5,6,7,9},y={2,3,3,4,5} 求线性回归方程
x={3,5,6,7,9},y={2,3,3,4,5} 求线性回归方程

x={3,5,6,7,9},y={2,3,3,4,5} 求线性回归方程
%by dynamic
%2009.3.3
下面我将使用MATLAB运算的结果显示如下
>> x=[3 5 6 7 9],y=[2 3 3 4 5]
x_mean=mean(x)
y_mean=mean(y)
b_hat=sum((x-x_mean).*(y-y_mean))./sum((x-x_mean).^2)
a_hat=y_mean-b_hat*x_mean
x =
3 5 6 7 9
y =
2 3 3 4 5
x_mean =
6
y_mean =
3.4000
b_hat =
0.5000
a_hat =
0.4000
所以回归方程为
y=05x+0.4
其实这个,可以直接使用一个MATLAB命令完成
>> p=polyfit(x,y,1)
p =
0.5000 0.4000

3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y 联立方程 有的话 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y 3x+2=y 5X+4=Y 7X+6=Y 9X+8=y 11x=y要如何计算 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y怎么解 y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组,无 3x+5y-(x+y)=6 2(x+y)-3x=-7 帮忙解一些方程组(1)3x-2y=6 2x+3y=17 (2)5x+6y=15.2 3x-2y=-0.4(3)2(x+y)-3y=7 4(x-9)=3(y-2)(4)3(x+y)-4(x-y)=4 x+y/2+x-y/6=1 x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)= 3(x-y)把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)=3(x-y)²-4(x-y)+7(x-y)-6(x-y)²= 4.4x+6y=54 9x+2y=87 5.2x+y=7 2x+5y=19 6.x+24.4x+6y=54 9x+2y=87 5.2x+y=7 2x+5y=19 6.x+2y=21 3x+5y=56 x+y=3 x+2y=9 3/x+1=y y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9用代入法解 x+y=3 x+2y=9 3/x+1=y y-x=3 y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9 y-x=3 把(x-y)看做一个整体,合并同类项5(x-y)+2(x-y)-4(x-y)=3(x-y)次方-4(x-y)+7(x-y)-6(x-y)次方= x+y=5① x=3y+2① 9x-5y=1① 3x-2y=11① x-2y=y+1① 2x-y=7② x+3y=8② 6x-7y=2② 2x+3y=16② 2x-3y=10②3x+2y=y+1①2x-3y=10②D 初二上学期方程题 4x+y=5 5x+4y=63x-2y=1 2x+3y=13x-2y=7 7x+5y=32x+3y=17 2x-y=-4x+5y=6 2x+y=23x-6y=4 3x+2y=52x+y=73x-4y=53x+y=1x-2y=-1x+y=42x+3y=92x-3y=74x+5y=3x+y=20004x+6y=90003x+5y=113x-2y=42x+3y=215x-2y=5x+y=54x+3y=182x+3y=16x+4y=132x+3y=40x 解下列方程组{4x-3y=5 2x+5y=9 {x+y=2 x-y=0 {x+2y=6 x-2y=-2 {5x-y=16 3x+2y=20 {2x+3y=-7 3x+2y=7