CS109: Probability for Computer Scientists
Win 2025
Monday, Wednesday, Friday 3:00pm - 4:20pm in-person in Nvidia Auditorium

Week 9 TODO

Start PSet 7
Signup for Final PEP
Vote on Class Playlist

Teaching Team

Professor: Chris Piech
Chris

Awesome TAs: cs109 @ cs.stanford.edu

This Week in CS109
Date Lecture Outside Class
Mon, Mar 3 Logistic Regression PSet 7 goes out
Wed, Mar 5 Comparing Classifiers
Fri, Mar 7 Beyond Binary Classification
Pset 7: Machine Learning
2025030315 by the Teaching Team

Problem Set #7 has been released! It is due next Friday (March 14th). In this pset, you'll implement logistic regression from scratch and apply machine learning methods to real world datasets. Hope you enjoy.

Pset 6: Uncertainty Theory
2025022120 by the Teaching Team

Problem Set #6 has been released! Practice applying bootstrapping across different contexts, taking expectation to the next level, and more.

CS109 Challenge!
2025021415 by the Teaching Team

One of the joys of probability+programming is the ability to make something totally of your own creation. In CS109 this quarter we are hosting a Challenge where you can make anything you like using the concepts and tools we learn in class. See the Challenge handout for more details.

Pset 5: Models, Beta, and CLT
2025021406 by the Teaching Team

Problem Set #5 has been released! Dive deeper into probabilistic models and explore the beauty of the Beta distribution and Central Limit Theorem.

Midterm Review: Wed @ 5pm, Hewlett 201
2025020315

We will be holding a midterm review session after class this Wednesday, Feb 5th! It will run from 5 - 6:30 pm in Hewlett 201. We will record the session and share the recording, slides, and more through Ed. Come with questions!

We've also released up-to-date info on the Midterm page of the course website. Check out where you should go for your exam, how many pages of notes you can bring, and past midterms to practice with.

Pset 4: Continuous Random Variables + Inference

Problem Set #4 has been released. Practice inference and work deeper with continuous random variables.

Pset 3: Random Variables
2025012415

Problem Set #3 has been released! It features the discrete random variables we've learned in class -- you'll analyze a bloom filter (a probabilistic datastructure), tell the difference between true randomness and a human faking it, and make your own art!

Pset 2: Core Probability
2025011611

Problem Set #2 has been released! It is due on Friday, Jan 24th at 10:00pm Pacific. Practice working with conditional probability, independence, and Bayes' Theorem.

Section + Theme Song

Sign up for section using the Section Sign up Form before Sunday Jan 12th and noon. Suggest songs for the class playlist (also by noon on Sunday).

Pset 1: Counting
2025010815

Problem Set #1 has been released! It is due on Wed, Jan 15 at 10:00pm Pacific.

Welcome

Welcome to CS109! We are looking forward to an uplifting and exciting quarter. Class starts Monday, Jan 6th at 3pm PT in Nvidia Auditorium. See you there 🌱.

Getting Started in CS109

The Syllabus page has details on course logistics. Read our FAQ for more information.
The Honor Code handout describes how the Honor Code applies in the context of the work you will do in CS109.
The Schedule page has a list of all topics that we will cover in CS109, and will have links to lecture materials and concept checks.
The Office Hours page has contact information for the teaching team. Office Hours will be listed on this calendar and start on Wednesday, Sept 25th.
Section enrollment details will be released on the first day of class; you do not need to enroll via Axess


RESOURCES

Discussion
Course Reader
Syllabus
Schedule
Office Hours

Key Dates

Midterm: Feb 11th, 7p
Final: Mar 18th, 8:30a
Last lecture: Mar 14th

Course Values

Everyone is welcome. Intellectual joy. Be kind. Be humane. Social connection. Learn by doing. Thrill of building. Adapt to new contexts.
CS109: Probability for Comp. Science
Fall 2024, MWF 3:00pm - 4:20pm, Nvidia Auditorium

Week 9 TODO

Start PSet 7
Signup for Final PEP
Vote on Class Playlist

Teaching Team

Professor: Chris Piech

RESOURCES


Key Dates

Midterm: Feb 11th, 7p
Final: Mar 18th, 8:30a
Last lecture: Mar 14th

Announcements

This Week in CS109
Date Lecture Outside Class
Mon, Mar 3 Logistic Regression PSet 7 goes out
Wed, Mar 5 Comparing Classifiers
Fri, Mar 7 Beyond Binary Classification
Pset 7: Machine Learning
2025030315 by the Teaching Team

Problem Set #7 has been released! It is due next Friday (March 14th). In this pset, you'll implement logistic regression from scratch and apply machine learning methods to real world datasets. Hope you enjoy.

Pset 6: Uncertainty Theory
2025022120 by the Teaching Team

Problem Set #6 has been released! Practice applying bootstrapping across different contexts, taking expectation to the next level, and more.

CS109 Challenge!
2025021415 by the Teaching Team

One of the joys of probability+programming is the ability to make something totally of your own creation. In CS109 this quarter we are hosting a Challenge where you can make anything you like using the concepts and tools we learn in class. See the Challenge handout for more details.

Pset 5: Models, Beta, and CLT
2025021406 by the Teaching Team

Problem Set #5 has been released! Dive deeper into probabilistic models and explore the beauty of the Beta distribution and Central Limit Theorem.

Midterm Review: Wed @ 5pm, Hewlett 201
2025020315

We will be holding a midterm review session after class this Wednesday, Feb 5th! It will run from 5 - 6:30 pm in Hewlett 201. We will record the session and share the recording, slides, and more through Ed. Come with questions!

We've also released up-to-date info on the Midterm page of the course website. Check out where you should go for your exam, how many pages of notes you can bring, and past midterms to practice with.

Pset 4: Continuous Random Variables + Inference

Problem Set #4 has been released. Practice inference and work deeper with continuous random variables.

Pset 3: Random Variables
2025012415

Problem Set #3 has been released! It features the discrete random variables we've learned in class -- you'll analyze a bloom filter (a probabilistic datastructure), tell the difference between true randomness and a human faking it, and make your own art!

Pset 2: Core Probability
2025011611

Problem Set #2 has been released! It is due on Friday, Jan 24th at 10:00pm Pacific. Practice working with conditional probability, independence, and Bayes' Theorem.

Section + Theme Song

Sign up for section using the Section Sign up Form before Sunday Jan 12th and noon. Suggest songs for the class playlist (also by noon on Sunday).

Pset 1: Counting
2025010815

Problem Set #1 has been released! It is due on Wed, Jan 15 at 10:00pm Pacific.

Welcome

Welcome to CS109! We are looking forward to an uplifting and exciting quarter. Class starts Monday, Jan 6th at 3pm PT in Nvidia Auditorium. See you there 🌱.

Getting Started in CS109

The Syllabus page has details on course logistics. Read our FAQ for more information.
The Honor Code handout describes how the Honor Code applies in the context of the work you will do in CS109.
The Schedule page has a list of all topics that we will cover in CS109, and will have links to lecture materials and concept checks.
The Office Hours page has contact information for the teaching team. Office Hours will be listed on this calendar and start on Wednesday, Sept 25th.
Section enrollment details will be released on the first day of class; you do not need to enroll via Axess


Course Values

Everyone is welcome. Intellectual joy. Be kind. Be humane. Social connection. Learn by doing. Thrill of building. Adapt to new contexts.