The data set kid.weights (Library: UsingR) contains age, weight, and height measurements for several children.

(a) Fit the linear model shown below and report summary of the model.

weight = b₀ + b₁age + b₂height + b₃height² + b₄height³ + b₅height⁴

(b) Use the partial F-test to select between this model and the nested models found by using only first-, second-, and third-degree polynomials for height.