Differentiate sample vs population standard deviation
Company: DRW
Role: Data Scientist
Category: Statistics & Math
Difficulty: medium
Interview Round: Technical Screen
Differentiate population vs sample standard deviation for a finite window: explain why the denominators are n and n−1 (Bessel’s correction), how this choice affects rolling estimates, and what to return for k = 1. State which definition you would implement by default, how you would make it configurable, and how you would document the choice in code and tests.
Quick Answer: This question evaluates understanding of statistical concepts such as population versus sample standard deviation and Bessel’s correction, along with practical competencies in implementing rolling time-series computations, handling edge cases like k=1, and documenting/configuring implementation choices in the Statistics & Math domain.