D.E. Shaw Quant Interview Questions
The D.E. Shaw Group is renowned for its rigorous quantitative interviews, designed to assess a candidate’s deep understanding of probability, statistics, and problem-solving skills. Quantitative interviews at D.E. Shaw often involve complex probability puzzles and expectation problems, reflecting real-world scenarios a quant researcher might face. In this article, we’ll explore and solve three classic D.E. Shaw quant interview questions about rolling dice, providing detailed explanations, solutions, and the mathematical concepts involved. Whether you’re preparing for a quant interview or just curious, this guide will help you understand the logic and methodology behind these fascinating problems.
Given a fair 6-sided die, what is the expected number of rolls needed until you roll a 6 for the first time?
This is a classic example of the “expected value of a geometric random variable”. We're looking for the expected number of independent trials (die rolls) needed to get the first success (rolling a 6).
