Discrete Math for Data Science
DSCI 220, 2025 W1
September 3, 2025
🎭 Sages & Tricksters
How to Play
- Each of you are secretly assigned a role:
- Sage = always tell the truth (Black)
- Trickster = always lie (Red)
- Everyone sees the packet of 6 cards and the fact.
- In rounds, each player may ask yes/no questions about the fact.
- Work together: compare answers, spot contradictions.
- Goal: Deduce each person’s role!
🔄 Round Structure
1. Two Info Rounds
- In each round, take turns asking one yes/no question about the fact
2. Debate Round
- Compare answers
- Look for contradictions
3. Conclusion
- Agree on everyone’s roles
- Reveal the cards & roles!
🧩 Logic in Action
- Logic means starting from true facts
- Asking the right questions
- Spotting contradictions
- And making valid inferences
In this course we’ll apply all of this to Data Science!
Term Structure:
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Grading:
| 🎉 Class Meetings |
0% |
| 🪄 Tutorials |
15% |
| 🤩 Examlets |
55% |
| 🤩 Final Exam |
30% |
Communications
| Cinda |
Mon 2–4pm |
🏢 ICCS 233 ·  |
| Joe |
Fri 11-12a |
🏢 FORW 317 |
Truth
Make at least 3 observations about the following table:
Summary
Key observations about the table:
- The diagram is called a Truth Table
- p and q are variables, each of which take on one of two Boolean values, True or False (T/F, 1/0)
- ∨ is a binary operator that implements a function (creates output) from the 2 input variables to another Boolean value. It is characterized by its output values.
- The operator ∨ corresponds to the English word or.
- The expression p ∨ q is called a proposition.
Cool down
How many rows for a proposition on 3 variables? \(k\) variables?
Give a good name for an operator that takes 1 variable: __________
Give a good name for an operator that takes 3 variables: __________
How many different binary operators could there be?
Piazza piazza.com/ubc.ca/winterterm12025/dsci220