Models with multiple predictors

Lecture 18

Dr. Mine Çetinkaya-Rundel

Duke University
STA 199 - Fall 2022

11/1/22

Warm up

While you wait for class to begin…

• Clone your ae-15 project from GitHub, render your document, update your name, and commit and push.
• Post any questions you have about the material so far at sli.do / #sta199.

Announcements

• My OH today: On Zoom at bit.ly/minezoom
• Jasmine’s OH moved to 4-5pm

Goals

• Review prediction and interpretation of model results
• Review main and interaction effects models
• Discuss model selection further

Application exercise

ae-15

• Go to the course GitHub org and find your ae-15 (repo name will be suffixed with your GitHub name).
• Clone the repo in your container, open the Quarto document in the repo, and follow along and complete the exercises.
• Render, commit, and push your edits by the AE deadline – 3 days from today.

Recap

• What is the practical difference between a model with parallel and non-parallel lines?
• What is the definition of R-squared?
• Why do we choose models based on adjusted R-squared and not R-squared?