CPSC 330 Lecture 12: Ensembles

Announcements

• Midterm 1
  • How was it?
• HW4 grading is almost done. The grades will be released later this week.
• HW5 is an open-ended project-type homework. Please ensure to start early.

iClicker Exercise 12.0

iClicker cloud join link: https://join.iclicker.com/VYFJ

Which of the following scenarios has worked effectively for you in the past?

• 1. Working independently on a project/assignment.
• 2. Working with like-minded people.
• 3. Teaming up with a diverse group offering varied perspectives and skills.

Ensembles

• Key idea: Combine multiple trees to build stronger models.
• These kinds of models are extremely popular in industry and machine learning competitions.
  
• We are going to cover how to use a few popular tree-based models:
  • Random forests
  • Gradient boosted trees (very high level)
• We will also talk about two common ways to combine different models:
  • Averaging
  • Stacking

Ensembles class demo