Derive variance and CTR confidence intervals
Company: Roblox
Role: Data Scientist
Category: Statistics & Math
Difficulty: medium
Interview Round: Technical Screen
Quick Answer: This question evaluates understanding of estimation and inference for proportions, including CTR point estimation, standard errors, multiple confidence-interval methods (Wald, Wilson, Clopper–Pearson), pooled estimation across days, and the distinction between sample and population variance for day-level variability.