In the modeling of the Burn Injury data questions came up as to how to model age. There were essentially three choices: linear (power 1), quadratic (powers 1 and 2) and the best fractional polynomial...

In the modeling of the Burn Injury data questions came up as to how to model age. There were essentially three choices: linear (power 1), quadratic (powers 1 and 2) and the best fractional polynomial model (power 2). In the text we proceeded with power 2. Perform selection of interactions for the other two parameterizations and save your work for an exercise on model evaluation in Chapter 5.