In the article “Sensitivity to reward and body mass index: evidence for a nonlinear relationship” published in Appetite (Davis and Fox, 2008), the authors reported the fitted multiple regression model ˆ???????? = 6.72 + 1.77Sex − 5.19B − 8.47B2 where SR is a measure of sensitivity to reward, Sex is a dummy variable that is 1 for a male and 0 for a female, and B is the standardized value of BMI.

(a) Determine the fitted value for a male with a B = 0.5.

(b) Determine the residual for a male and B=0.5 when SR=4.1.

(c) If the authors model is the best fitting model, what would the residual plot for the model ???????? = ????0 + ????1Sex + ????2B + ???? be expected to look like?