About Take-Home Quizzes and Final Exam

Midterm: Friday, July 15, 4:00PM - Monday, July 18, 1:00PM

Final: Friday, August 12, 3:30PM - 6:30PM, ECON140 (Landau Economics Building)


Midterm Specifics

Overview: The midterm is a take-home, open-book, open-note, 2-hour long exam that is administered online through Gradescope. The exam will be released at 4pm on Friday, July 15th and will be available until 1pm on Monday, July 18th. You are free to take the exam during any two-hour long block in this window. Once you start the exam, you must complete and submit your responses within two hours. Late submissions cannot be accepted. The latest we'll accept submissions will be at 1pm Pacific time on July 18th, so make sure you start by 11am to give yourself enough time to complete the exam.

Format: There will not be coding questions on the midterm exam. You are going to be solving probability questions by hand. To that extent we are not interested in numeric answers, but rather in formulaic answers. It is fine for your answers to include summations, products, factorials, exponentials, and combinations, unless the question specifically asks for a numeric quantity or closed form. Where numeric answers are required, the use of fractions is fine. You must show your work. Any explanation you provide of how you obtained your answer can potentially allow us to give you partial credit for a problem. For example, describe the distributions and parameter values you used, where appropriate.

Questions during exam: If you have questions during the exam, please ask them as a private question via Ed. If you encounter an issue during an assessment period that prevents you from completing the assessment, please email the instructor immediately so that we can work with you to resolve the issue.

Honor Code Guidelines: Unlike the assignments, the midterm is strictly individual work. Even course staff assistance will be limited to clarifying questions of the kind that might be allowed on a traditional, in-person exam. The midterm is open-book (open lecture notes, handouts, textbooks, course lecture videos, and internet searches for conceptual information, e.g., Wikipedia). Consultation of other humans in any form or medium (e.g., communicating with classmates, asking questions on forum websites such as StackOverflow) is prohibited. All work done with the assistance of any external material in any way (other than provided CS109 course materials) must include citation (e.g., "Referred to Wikipedia page on DeMorgan's Law for Question 2."). Copying solutions is unacceptable, even with citation. If by chance you encounter solutions to the problem, navigate away from that page before you feel tempted to copy. If you become aware of any honor code violations by any student in the class, your commitments under the Stanford Honor Code obligate you to inform course staff. Please remember that there is no reason to violate your conscience to complete a take-home exam.

Material covered: The midterm will cover all material through and including Lecture 9. This includes everything on Problem Sets 1, 2, and 3 (except for exponential random variables, CDFs, and normal distributions).

Practice material: Previous iterations of this course have had midterms that may have covered slightly different material than you are responsible for. To help you practice the concepts, we have provided these previous midterms in whole. Underneath each previous exam, we have listed the questions that cover relevant material for our midterm this quarter.

Review Session: We will be holding a review session for the midterm on Thursday, July 14th from 10:30am-12pm on Zoom. The Zoom link will be sent out in an Ed announcement and be posted here.

Final Exam Specifics

Time/Location: Friday, August 12, 3:30-6:30pm, in ECON140 (Landau Economics Building)

Overview: The final is a closed-book, closed-computer, closed-calculater, 3-hour long exam that will be administered in-person at the date, time, and location listed above. As promised, I'm sharing the reference sheet that we'll be supplying you with during the final exam. You're free to download it and assess what it summarizes, but you shouldn't bring your own copy to the final, since we'll be supplying you with one instead. In addition to this reference sheet, we will allow you to bring in three pages (front and back) of your own free form notes. You might use this to include more detail on a topic you've found difficult, or you might use it to include your implementation of the Naive Bayes and/or logistics regressions needed for Problem Set 6. It's completely up to you. The only requirement is that the pages must be 8.5" x 11" or smaller, and readable without the use of any aids (ie: a magnifying glass - yes, students have really done this before).

Format: There may be coding on the exam, but you'd be implementing functions and programs in pseudocode, and we'd be incredibly lax on syntax. If we ask that you frame your implementation in terms of, say, the Beta function, we would remind you of the key Python directives needed to generate random probability densities, cumulative probability densities, and so forth.

In addition, you are going to be solving probability questions by hand. To that extent, we are not interested in numeric answers, but rather in formulaic answers. It is fine for your answers to include summations, products, factorials, exponentials, and combinations, unless the question specifically asks for a numeric quantity or closed form. Where numeric answers are required, the use of fractions is fine. You must show your work. Any explanation you provide of how you obtained your answer can potentially allow us to give you partial credit for a problem. For example, describe the distributions and parameter values you used, where appropriate.

What about the Phi table? If it comes up on the exam, I am not going to make you look up values from a phi table. Instead you can leave your answer in terms of phi (the CDF of the standard normal). For example Φ(0.75) is a fine final answer. This was not the case in the past so you will see questions which ask for a numeric answer in the practice exams.

Material Covered: The final exam will cover all material taught through the very last day of class. The final exam is cumulative but will focus on material not covered by the midterm.

Practice material: We have provided some previous exams below, which will be a valuable tool as you study for the final. All the questions are fair game, and we recommend that yuo focus on those questions not already covered by the midterm. If you are unsure about a question or if the topic if tests will be on our exam, feel free to message us or post on Ed!

Review Session: We will be holding two separate review sessions for the final, both of which will be held at this Zoom link and also recorded. The first review session will be on Monday, August 8 from 7:00-8:30pm and cover material from Lectures 2-11. The second review session will be held on Tuesday, August 9th from 3:30-5:00pm and cover material from from Lectures 12-22.

Practice Exams

Review Materials

These review materials were put together by Alex Tsun, a CS109 TA back in Spring 2019. These materials may cover slightly different material than you are responsible for. You are only responsible for material and topics covered in lecture, in section, and on problem sets.

Credits: Jerry Cain; Wording for Honor Code Guidelines from CS103 Spring 2020, taught by Cynthia Bailey Lee and David Varodayan.