Hudson River Trading Quant Researcher Interview Questions
The quant researcher interview at Hudson River Trading (HRT) is known to be among the most intellectually stimulating in the quantitative finance industry. Candidates are expected to master a broad spectrum of mathematical, statistical, and logical reasoning problems. In this comprehensive guide, we solve and explain some of the most representative Hudson River Trading quant researcher interview questions. Our focus is on deep understanding and clear exposition, ensuring you can both solve the problems and explain the underlying concepts with confidence.
Consider a random permutation of the numbers \(1, 2, ..., 31415\). Let \(A\) be the number of fixed points (elements that remain in their original position), and let \(B\) be the number of non-fixed points. What is the variance of \(B-A\)?
Let \(n = 31415\). By definition:
