已知点(3,2.5)(4,3)(5,4)(6,4.5)若用最小二乘法求其线性回归方程y=ax+b,

x平均=（3+4+5+6）/4=4.5y平均=（2.5+3+4+4.5）/4=3.5a=ΣΔxiΔyi/Σ(Δxi)^2=[(4.5-3)(3.5-2.5)+0.5*0.5+0.5*0.5+1.5*1]/(1.5^2+0.5^2+0.5^2+1.5^2)=3.5/5=0.7b=y平均-a(x平均）=3.5-0.7*4.5=3.5-3.15=0.35∴回归...