3/26/2009

Chapter 8: Quantitative and Qualitative Predictors

• Polynomial regression models – See Bodyfat-int_Ch8.sas
• Centering
• Hierarchical modeling
• Dangers
• Extrapolation
• Models higher than third-order
• Transforming back from centered variables

• Interaction regression models
• Testing for significant interaction – See Bodyfat-int_Ch8.sas
• Types of Effects (see Figure 8.7): #8.10
• Additive model
• Reinforcement interaction effect
• Interference interaction effect
• Interpreting b_k’s when interaction exists

• Another Example: Powercell_Ch8.sas

For Tuesday: Read the rest of Chapter 8.