CS109: Probability for Computer Scientists
Autumn 2020
Monday, Wednesday, Friday 1:00PM-2:00PM Pacific, Online




NOTE: this website is out of date. This is the course web site from a past quarter, Autumn 2020. If you are looking for fall quarter's website, you should visit https://web.stanford.edu/class/archive/cs/cs109/cs109.1214/ instead. Please be advised that courses' policies change with each new quarter and instructor, and any information on this out-of-date page may not apply to you.

RESOURCES


Schedule
Staff / Office Hours
Videos on Canvas
Discussion Forum
Zoom details (Stanford-only)
Passcode: on Staff website
Gradescope

EXAMS

Quiz #1
Wednesday, October 7
to Friday, October 9

Quiz #2
Wednesday, October 28
to Friday, October 30

Quiz #3
Wednesday, November 18
to Friday, November 20


TEACHING TEAM

cs109 @ cs.stanford.edu

Instructors

Lisa Yan

Lisa Yan
yanlisa @ stanford.edu
Online
MF 2:00PM-3:00PM

Jerry Cain

Jerry Cain
jerry @ cs.stanford.edu
Online
W 2:00PM-4:00PM


ANNOUNCEMENTS

Contest Results
2020112011 by Lisa

We received 19 contest entries this quarter and were impressed by the creativity and probability know-how the entries showed!

Grand Prize Winners:
Ian Chang, Classifying Art using Probability
Sohit Gatiganti and Chris Chankyo Kim, Stack Overflow: A Deep Dive into Post Quality Analysis

Runners-Up:
Valexa Orelien, The Book Matcher
Edward Park, From the First to the Last, From Cradle to Grave
Anna Quinlan, Improving Virtual Diabetes Patient Simulations with Bayesian Networks
Erika Hunting and Wes Peisch, Metro Mania

Congratulations to everyone who participated! We loved learning about what motivates you to study probability!

Quiz #3 next week
2020111211 by Lisa

Quiz #3 for CS109 is coming up: It is Wednesday, November 18th 2:00PM - Friday, November 20th 1:00PM Pacific. We have given you a 47-hour timeslot, but the quiz should correspond to about 1-3 hours of active work time, depending on your preparation and process. The quiz will cover material up to and including logistic regression (Lecture 26), which includes Problem Sets 5 and 6.

The best way to study is to work through the practice exams and section handouts. This linked webpage also has quiz administration details and review session materials.

There will be no separate review session for this quiz, but your section TA will do a 50-minute review in your last section. All handouts will be posted in the section handouts tab.

If you have an emergency situation where you are unable to set aside a few hours to complete the exam in this timeslot, please email Jerry and Lisa at any time. We will try our best to accommodate you.

Final PSet
2020110909 by Lisa

The final problem set was released last Friday, due date next Monday 11/16 (on-time). You will implement two machine learning algorithms, Naive Bayes and Logistic Regression. You will then use these algorithms to make predictions on heart tomography, Netflix movies and ancestry data.

PS#5 Deadline pushed back + preliminary gradebook
2020110511 by Lisa

Due to the ongoing climate around the U.S. elections (specifically, that Election Day has evolved into Election Week), we've decided to push back Problem Set 5's on-time deadline as follows. All times Pacific.

  • Submit by Friday November 6th 1pm (original on-time deadline): Super bonus of +8%.
  • Submit by Monday November 9th, 1pm (original grace period deadline): Regular on-time bonus of +5%.
  • Submit by Tuesday November 10th, 1pm (new grace period deadline): Grace period, graded as usual. No submissions accepted after this date unless you have an extenuating circumstance that you've communicated to Jerry and/or Lisa ahead of time.

We've also released a preliminary gradebook with your current numeric final grade as computed from Gradescope. Please email your Section Leader if you have section attendance questions. For all other concerns, post on Ed or email the staff list. Access the gradebook below.

Go to Gradebook

Apply to CS51/52
2020110310 by Jerry

Everyone, a fellow CS109 student, Alissa Vuillier, emailed me with news that CS51 and CS52 are now accepting applications for next quarter. Here's the crux of what she wrote [slight edited]:

  • I'm part of the CS51 teaching team, also known as "CS + Social Good Studio: Designing Social Impact Projects", and we're currently trying to get students to apply to our course! The class is a two-quarter commitment where students learn how to create social impact projects by working with a non-profit partner organization to build them a web/mobile app. Above all, our course is centered around showing students how they can use their knowledge of computer science to help people and make real change in the world.

  • The link to our application is right here and our application window closes on 11/6 at 11:59pm PST. Here's a link to more information.

Let me know if you'd like me to introduce you to Alissa or others on the CS51/52 teaching team.

No Section this week (Week 8)
2020110223 by Lisa

Section this week is cancelled; we've posted the section handout and solutions if you'd like to self-study. Lisa will also be holding an extra set of office hours on Wednesday 11/4, 10am-12pm Pacific on Nooks, so feel free to come on by and ask questions about section, work on the current problem set, or just de-stress.

Quiz #2 Graded
2020110310 by Lisa

Quiz #2 has been graded, and you can see how you did by visiting Gradescope and reviewing your quiz there. In general, quiz results were fantastic! The median grade was a 77 out of 80, and the standard deviation was 9.22. If after you review your graded quiz you feel there was a grading error, you can submit a regrade request directly on Gradescope any time between now and next Tuesday, November 10th at 11:59pm, Stanford time.

PSet #5 is out
2020102614 by Lisa

The penultimate problem set is now available! This problem set has only 8 questions.

Quiz #2 next week
2020102313 by Lisa

Quiz #2 for CS109 is coming up: It is Wednesday, October 28th 2:00PM - Friday, October 30th 1:00PM Pacific. We have given you a 47-hour timeslot, but the quiz should correspond to about 1-3 hours of active work time, depending on your preparation and process. The quiz will cover material up to and including lecture 15, which includes Problem Sets 3 and 4.

The best way to study is to work through the practice exams and section handouts. This linked webpage also has quiz administration details and review session materials.

Review session: Candice and Sri, two of our outstanding TAs, will be hosting a review session on Monday, October 26th, 7:00pm-9:00pm Pacific, accessible via this Zoom link. The session recording and materials will be posted on the quiz website afterwards.

If you have an emergency situation where you are unable to set aside a few hours to complete the exam in this timeslot, please email Jerry and Lisa at any time. We will try our best to accommodate you.

Midquarter Feedback
2020101610 by Lisa

We're interested to know what you think of CS109 so far. We invite you to fill out an anonymous feedback form here: https://forms.gle/poskurHZjavx2Sxw8. We'll keep the form open through Friday evening, October 23.

PSet #4 is out
2020101613 by Lisa

Problem Set #4 has been released! It has you predict flu or cold based on binary symptoms and risk factors. You will also design a probabilistic text analyzer to determine who really wrote the Federalist Papers!

Our Python review session #3 will be held on Monday, October 19th, 6-7pm Pacific and will cover the material you need to know for the last three psets (including this one). Zoom recording and materials will be made after the session, available on the Python for Probability page.

Quiz #1 Graded
2020101218 by Jerry

Quiz #1 has been graded, and you can see how you did by visiting Gradescope and reviewing your quiz there. In general, quiz results were fantastic! The median grade was an 86 out of 95, and the standard deviation was an 11.1. If after you review your graded quiz you feel there was a grading error, you can submit a regrade request directly on Gradescope any time between now and next Monday, October 18th at 11:59pm, Stanford time.

Quiz #1 Released
2020100714 by Lisa

Quiz #1 is released and is available on the exam page. The take-home, open-book, open-notes exam is to be completed individually, and is due on Friday, 10/9 1:00pm Pacific Time. Please read all instructions; if you have difficulty downloading your personalized quiz, send a message to the staff mailing list or post privately on Ed so that we can email you your copy of the exam.

The quiz should correspond to about 1-3 hours of active work time (plus any typesetting). The Gradescope assignment submission portal will be up through the end of the 47-hour window, so please make sure your final submission is uploaded by then. Also please make sure to tag your PDF submission pages to each question answered.

If you have an emergency situation where you are unable to set aside a few hours to complete the exam in this timeslot, please email Lisa and Jerry at any time. We will try our best to accommodate you.

PSet #3 is out
2020100517 by Lisa

Problem Set #3 has been released! It uses real probability density functions from the IPCC Climate Change report, and has you analyze a bloom filter (a probabilistic datastructure). The partial answer-checking will be up on Gradescope soon. Pset 3 is due Friday, October 16, 1:00PM Pacific Time.

Quiz #1 next week
2020093013 by Lisa

Quiz #1 for CS109 is coming up: It is Wednesday, October 7th 2:00PM - Friday, October 9th 1:00PM Pacific. We have given you a 47-hour timeslot, but the quiz should correspond to about 1-3 hours of active work time, depending on your preparation and process. The quiz will cover material up to and including lecture 6, which includes Problem Sets 1 and 2.

The best way to study is to work through the practice exams and section handouts. This linked webpage also has quiz administration details and review session materials.

Review session: Sandra and Anand, two of our outstanding TAs, will be hosting a review session on Sunday, October 4th, 6:00pm-8:00pm Pacific, accessible via this Zoom link. The session recording and materials will be posted on the quiz website afterwards.

If you have an emergency situation where you are unable to set aside a few hours to complete the exam in this timeslot, please email Jerry and Lisa at any time. We will try our best to accommodate you.

PSet #2 is out
2020092500 by Lisa

Congratulations on finishing PSet #1 (or coming close)! Problem Set #2 has been released! This problem set is just 10 problems to adjust for your workload in this course. Here is a Latex template for pset 2. This pset has a larger coding portion, so our Python review session #2 will be held on Wednesday, September 30th, 3:30pm-4:30pm Pacific. Zoom recording and materials will be made available after the session, available on the Python for Probability page.

Section starts this week!
2020092021

Section assignments have been released and are available on this page, which is also accessible through our About Section page. A reminder that sections start this week (Tuesday 9/21 and Wednesday 9/22). Zoom links will be accessible on the Section/Office Hours page starting Monday evening.

If you did not receive a section, or the current section time no longer works for you, please click the "Join" or "Switch" buttons on the Section Assignments page to switch sections. You can do so until the end of Week 3 (Friday, October 2). If there are any other questions with section assignments, please email Lisa or Jerry.

Errata on PSet #1
2020091621 by Lisa

Problem 3 (parts (a) and (b)) have been reworded for clarity.

Sign up for Section!
2020091613

Please sign up for section by filling out this form (sign in with Stanford email): https://forms.gle/DADWHJazqfptWgJm8.

Once a week you are going to meet in a small group section. We are going to find the best weekly times for everyone. Section signups will close on Saturday, September 19 at 5:00pm Pacific. Preferences are not first come first serve. For more information, visit the About Section page.

We will notify you of your section assignment on Sunday evening, September 20, when you will have the opportunity to switch sections should your assigned timeslot no longer work.

PSet #1 is out + Python review session
2020091613 by Lisa

Problem Set #1 has been released! It is due Friday, September 25th at 1:00pm Pacific. Submission will be via Gradescope. Office Hours start today, and the Office Hours Calendar will have times and instructions to join.

You are encouraged to write up your problem sets using LaTeX. Templates for each Problem Set are located on their respective webpage. See this Guide to LaTeX under Resources/Demos. Though you may install LaTeX, it is often much easier to use an online LaTeX editor. A great option is: overleaf.com.

There is a programming problem on this problem set you will complete in Python and submit to an autograder on Gradescope. We will be holding two offerings of our first Python review session this Friday, September 18th, at 12:00am-1:00am Pacific and 2:00pm-3:00pm Pacific. Please see the Python for Probability page under Resources/Demos for Zoom links, slides, and recordings (to be posted Friday evening).

New to CS109?
2020091512 by Lisa

If you just added CS109 and are not on the Gradescope/Edstem:

The access code to the Gradescope is: 93EV7B

The link to join the Discussion Forum is here: Join (Stanford-only)

What is CS109?
2020091317 by Lisa

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, September 16th.

Finally, the button helps you navigate the tools used in differnt parts of this class: lectures, sections, problem sets, and getting help in office hours or on our discussion forum.

Apply to CS109A (ACE/Pathfinders)
2020090900 by Lisa

CS109A, also known as CS109 ACE, is a new, 1-unit supplementary section designed to build a stronger foundation in computer science. Students participating in ACE will attend an additional weekly section and participate in exam review sessions and individual tutoring. Section will take place on Tuesdays 10:30-11:50am Pacific on Zoom, synchronously.

CS109A ACE is a Computer Science department program based on one of the School of Engineering's Equity and Inclusion Initiatives. We especially want to provide an opportunity for students who come from educationally disadvantaged backgrounds or for anyone who feels they might need additional support in order to succeed. We limit enrollment to enable small classes that allow students to have one-on-one interactions with the CA.

If you are interested in joining the ACE section, please apply online. The application is due on September 18. All student who apply by September 14 will be welcome to attend section the first week and will receive a Zoom link for section via email during Week 1. If you have any questions about ACE, feel free to reach out to Gili Rusak (CS109A ACE CA) at gili@stanford.edu.

Welcome
2020090700 by Lisa

Welcome to CS109! We are looking forward to a fun quarter. Class starts Monday, September 14 at 1:00pm PT Online. Section enrollment details will be released on the first day of class; you do not need to enroll via Axess.

This page is under construction. More details to be released soon!