Question: Quadratic regression models can include the squares of right hand side variables. A sports statistician studied the relation between the time (Y, in seconds) for a particular competitive swimming event and the swimmer's age (X, in years) for 20 swimmers with ages ranging from 8 to 18. She employed a quadratic regression model and obtained the following results:

Y= 147 -11X₁ + 0.27X₂

a. Plot the estimated regression function. Would it be reasonable to use this regression function when the swimmer's age is 40? Comment.