Chapter 4 - Section 4.2 - Assess Your Understanding - Vocabulary and Skill Building - Page 215: 10g

$Σresidual^2=0.8$

Since $ŷ =−1.8x+3.6$ $Σresidual^2=Σ(y_i-ŷ _i)^2=Σ[y_i-(−1.8x_i+3.6)]^2=Σ(y_i+1.8x-3.6)^2$ $Σresidual^2=(7+1.8\times(-2)-3.6)^2+(6+1.8\times(-1)-3.6)^2+(3+1.8\times0-3.6)^2+(2+1.8\times1-3.6)^2+(0+1.8\times2-3.6)^2$ $Σresidual^2=0.8$