Bid-rigging in highway construction. Refer to the multiple regression example in Section 4.14 (p XXXXXXXXXXRecall that the cost (y) of constructing a road was modeled as a function of DOT engineers’...

Bid-rigging in highway construction. Refer to the multiple regression example in Section 4.14 (p. 235). Recall that the cost (y) of constructing a

road was modeled as a function of DOT engineers’ estimated cost (x₁) and a dummy variable (x₂) for whether the winning bid was fixed or competitively bid. Access the data saved in the FLAG file to carry out a complete residual analysis for the model E(y) = β₀
+ β₁x₁
+ β₂x₂
+ β₃x₁x₂. Do you recommend making any model modifications?