Topic: Quantitative Predictor Interactions

Worked Example: Study Time and Prior Preparation

Worked Example: Temperature and Insulation in Energy Use

Test a Conditional Slope Against a Scientific Benchmark

Test Whether Quantitative Predictors Interact

Separate Interaction from Correlation Between Predictors

Specify a Product-Term Model for Two Quantitative Predictors

Rescale Units Without Changing the Interaction Pattern

Read the Product Coefficient as a Change in Slope

Preserve Lower-Order Terms With the Hierarchy Principle

Plot Fitted Lines at Representative Predictor Values