CS109: Probability for Computer Scientists
Spring 2017
Monday, Wednesday, Friday 10:30am to 11:50am in NVIDIA Auditorium

To contribute to today's demo, please fill out this form: https://goo.gl/jCMY18


Lecture Videos
Staff / Office Hours
icon Piazza
icon Socrative


Problem Set 1
Problem Set 2
Problem Set 3


Tuesday, May 9th

Tuesday, June 13th

Teaching Team



Chris Piech
Gates 193
Wed 1-3pm

PSet 3: Random Variables

Pset #3 is out. It has one programming problem that asks you to predict elections based off of polling data. We made a small change to problem 11, the bloom filter, on April 25th to make it a more narative driven problem :-).

Prototype Section

Want to practice more probability in a smaller setting with TAs. In theory it will be a chance for us to solve problems together in a way that is more guided than office hours and more involved than lecture. Come, ask see what it is about! : Gates 104. : Tomorrow, Thursday 4/19 from 1:30p to 2:20p.

Binomial Gaussian

In class on Monday we talked about how Binomial distributions and Galton boards. Here is the video:

PSet #2

Problem set #2 is out! A few of the problems require you to process data. The datasets are now availible.

Update: We slightly updated the wording in problem 3 to make it clear that you can assume that two movies are conditionally independent given that the user does not like the genre.

Submit PSet #1

Problem set #1 is due on Friday. Submit your assignment by uploading it to the CS109 gradescope page. Gradescope is a tool that we will use to electronically grade and give you feedback on your problem sets. If you want to manually sign up, our class code is: MY6WP9.

Python Tutorial

There will be a Python tutorial led by Head TA William Monroe Thursday (4/13) from 4:30pm-5:20pm in Gates B01.

PSet #1

PSet #1 has been released! Office hours will start tomorrow -- see the office hour calendar for times and locations. There were a few clarifications to problems added on the morning of April 6th. See the errata on the pset for more details.


You can optionally write up your problem sets using the LaTex system. See this intro to LaTex, and the LaTex code used to generate it. You can use this LaTex template custom made for CS109 problem sets. Though you may install LaTeX, it is often much easier to use an online LaTeX editor. Two good options are: www.overleaf.com and www.sharelatex.com.

Former CS109 student Joe Delgado has written a nunber of snippets for Latex in Sublime, which he has made available on github.

NYT Article on Stats

An article from the New York Times discusses the increasing importance of statistics in computing. The article is entitled For Today's Graduate, Just One Word: Statistics. On a similar vein, The Wall Street Journal published an article entitled New Hiring Formula Values Math Pros talking about how employers are seeking computer scientists with training in statistics and probability. CS109 is specifically mentioned.

What is CS109?

We put together some handouts to help you understand where we are going to go in CS109 and how we plan to get there. See the Administrivia handout for details on logistics.

The Course Schedule page shows you the topics that we are going to cover in CS109 and the corresponding readings. We will also post materials from lecture on the schedule page.


Welcome to CS109! We are looking forward to a fun quarter. Class starts Monday April 3rd at 10:30am in NVIDIA Auditorium.