Extend Data Scientist Interview Questions
The questions to prepare for a Extend Data Scientist interview. Questions from real interview reports rank first. Updated weekly.
Calculate the monthly spending trends for customers using window functions and joins.
ExtendUse ROW_NUMBER() to keep the earliest created_at 'Repl created' per entity and return out-of-order duplicates to delete.
Replit
QuantcastCompute top 10 customers by net sales using joins and aggregations, ordering by revenue with deterministic tie-breaking.
Gain Digital
TCS
Zest AIExplain the bias-variance tradeoff and how it guides model choice, regularization, and generalization performance.
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Identify major online experiment pitfalls and explain how they can bias results in a streaming product A/B test.
ExtendCompute the mean and standard deviation of a dataset, and distinguish the sample standard deviation from the population version.
ExtendDiagnose a post-release KPI drop by separating instrumentation issues from real behavior changes and tracing the problem through the metric hierarchy.
ExtendA framework for prioritizing AI product features based on user value, feasibility, evaluation quality, and trade-offs.
ExtendDesign a fraud pipeline that compares batch, streaming, and hybrid architectures for 120K tx/sec with sub-300 ms decisions and reconciled hourly tables.
ExtendExplain which classification metrics to use and how metric choice depends on the business objective and error tradeoffs.
Extend