Probability
Playing Cards
Welcome! We hope you have a deck of cards in hand. We’ve created this page for you to visit at any stage of exploring our probability playing cards.
Conventions
As you get started with the deck, here is some information about conventions the deck follows.
Each suit explores a different, exciting area of probability. The main topics are expectation and linearity [♣️], classical and conditional probability [♦️], geometric probability [♥️], and random walks and martingales [♠️].
Problem difficulty varies wildly! Very roughly, the problems increase in difficulty from A –> K. Some problems are VERY hard (indicated on the card with [*]) and some no one in the world has solved yet (indicated via [**]). Most problems in this deck are far more difficult than anything you need to be able to solve to work at Jane Street. For interview preparation, we recommend the first 5-6 questions in [♣] and [♦️]. The rest are just for fun!
Helpful definitions
Our Probability & Markets Guide provides an overview of some useful concepts and terminology.
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Show us what you’ve worked out - even if you’re stuck. We love to see how you’re solving problems and when we see a particularly elegant solution, who knows, we might feature it here.
Questions and feedback
Please use this form to ask questions or provide feedback about the deck or specific problems.