6. (7 pts) In a study with predictors X1, X2, and response variable Y, the following partial regression plots were generated. Notation used below: residual(Y|X) are the residuals obtained from fitting the model E(Y=β0+β1X1+β2X2), residual(Y|X1) are the residuals obtained from fitting the model E(Y=β0+β2X2), and residual(Y|X2) are the residuals obtained from fitting the model E(Y=β0+β1X1).
Write the model equation you would use that best explains the variation in Y.