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Data Scientist Interview Questions
Practice 9403 coding, system design and machine learning questions from 546 companies, sorted by role, topic and interview round. Every question has step-by-step hints, a code runner that supports 8 languages and an AI mentor; members also get the full solution walkthrough.
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- 546
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Showing 541–570 of 641 results
- RobinhoodMediumData ScientistDesign Real-Time Analytics Pipeline with Kafka and Flink
This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Design Real-Time Analytics Pipeline with Kafka and Flink states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipOnsite - RobinhoodEasyData ScientistDesign an experiment to launch fractional shares
This question evaluates a candidate's competency in experimentation design, product analytics, statistical power and sample-size calculation, causal inference, and risk identification within a brokerage product context.
Analytics & ExperimentationOnsite - RobloxMediumData ScientistAnalyze Recent Orders Dataset with Python/pandas
This question evaluates proficiency in data manipulation and aggregation using Python/pandas, including extracting per-user maximums, computing overall summary statistics, and producing daily aggregates from time-stamped records.
Data Manipulation (SQL/Python)Onsite - RobloxMediumData ScientistDefend a metric choice under scrutiny
This question evaluates a Data Scientist's competency in metric selection, stakeholder communication, and experiment governance when defending a non-obvious primary metric.
Behavioral & LeadershipOnsite - RobloxMediumData ScientistGenerate Friendship List with Acceptance Dates Using Pandas
This question evaluates proficiency in data manipulation and relational reasoning using Python/pandas, focusing on transforming event logs into canonical pairwise relationships and extracting activation timestamps.
Data Manipulation (SQL/Python)Onsite - RobloxMediumData ScientistMatch requests and accepts into friendships in SQL
This question evaluates a candidate's competency in SQL data manipulation, focusing on temporal joins, deduplication of bidirectional relationships, selecting the earliest valid event, and reasoning about event-order constraints.
Data Manipulation (SQL/Python)Onsite - RobloxMediumData ScientistOptimize bread-factory pipeline for max profit
This question evaluates skills in combinatorial optimization, budgeted resource allocation, bottleneck throughput modeling, and algorithm design with cost amortization for maximizing profit under constraints.
Coding & AlgorithmsOnsite - ShopifyMediumData ScientistAnalyze Causes of November and June Shopify Traffic Spikes
This interview question evaluates metric design, causal reasoning, experiment setup, diagnostics, SQL/statistical checks, and recommendations in a realistic interview setting. A strong answer for Analyze Causes of November and June Shopify Traffic Spikes states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Analytics & ExperimentationOnsite - ShopifyMediumData ScientistAssess Candidate's Remote Collaboration and Technical Proficiency
Evaluates remote cross-functional collaboration and technical proficiency for a data-science role. Strong answers cover challenging projects, stakeholder rituals, async artifacts, tool stack, reproducibility, and quantified impact.
Behavioral & LeadershipOnsite - ShopifyMediumData ScientistCalculate Jaccard Similarity Score for Two String Lists
This question evaluates understanding of similarity metrics and competency in comparing string collections, reflecting knowledge of set-theoretic concepts and manipulation of collection data structures used in data processing.
Coding & AlgorithmsOnsite - ShopifyMediumData ScientistDetermine Growth of Pirated Theme Installations Over Years
This question evaluates proficiency in SQL-based data manipulation and analytics, focusing on computing time-based cohort percentages and conducting year-over-year trend analysis of merchant behavior.
Data Manipulation (SQL/Python)Onsite - ShopifyMediumData ScientistDiagnose Weekly Session Conversion Anomalies
This question evaluates proficiency in time-series anomaly detection, conversion-rate analysis, data quality handling (especially parsing and validating week labels), segmentation by shop type and session-duration buckets, and causal reasoning about traffic composition effects.
Analytics & ExperimentationOnsite - ShopifyMediumData ScientistMeasure Shopify App Store Success
This question evaluates a data scientist's competency in product-metrics design for a multi-sided app marketplace, including defining a north-star metric, per-side success and guardrail metrics, required dataset schemas and join keys, and criteria for evaluating ranking/search/recommendation experiments.
Analytics & ExperimentationOnsite - SnapchatMediumData ScientistCompute CTR and metrics with pandas
This question evaluates proficiency in time-series and event-level data manipulation with pandas, including CTR computation, event denoising and deduplication, sessionization, cohort analysis, temporal joins, and performance-aware vectorized operations within the Data Manipulation (SQL/Python) domain.
Data Manipulation (SQL/Python)Onsite - SnapchatMediumData ScientistCompute User Retention and Analyze Event Data
This question evaluates a candidate's ability to perform SQL and Python data manipulation for event analytics, including cohort retention, aggregation of distinct purchasing users, median-of-daily-events calculations, and hourly time-series grouping.
Data Manipulation (SQL/Python)Onsite - SnapchatMediumData ScientistDesign A/B Tests for Banner Ad and Group-Story Feature
Evaluates A/B test design for a banner ad and a group-story feature in a social app. Strong answers define monetization, engagement, safety, and retention metrics, handle accidental clicks for ads, account for network effects in group stories, and set launch criteria with guardrails.
Analytics & ExperimentationOnsite - SnapchatMediumData ScientistHow to Update Bayesian Model for Concept Drift?
How to Update Bayesian Model for Concept Drift? evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - SnapchatMediumData ScientistInfluence Cross-Functional Teams Without Formal Authority
Evaluates behavioral and leadership storytelling for influencing cross-functional teams without formal authority. Strong answers use specific data science examples, quantify impact, show coachability from feedback, and explain prioritization when leadership, data, and UX point in different directions.
Behavioral & LeadershipOnsite - SnowflakeMediumData ScientistBuild a cohort dashboard with Streamlit and SQL
This question evaluates proficiency in cohort analysis using SQL window functions, time-based aggregation, ARPU calculation, and integration of data querying with a Streamlit visualization front end, including handling timezones and data-quality checks.
Data Manipulation (SQL/Python)Onsite - SnowflakeMediumData ScientistDesign an analytic warehouse for event data
This question evaluates a candidate's competency in data warehousing and engineering for analytics, including event-level schema and partitioning, slowly changing dimensions, idempotent ingestion and deduplication, derived metrics modeling, and query performance and cost trade-offs using SQL/Python.
Data Manipulation (SQL/Python)Onsite - SnowflakeMediumData ScientistSolve and optimize 3Sum and variants at scale
This question evaluates algorithmic problem-solving skills in array processing, deduplication and combinatorial counting, external-memory and streaming algorithm design, and complexity analysis including integer overflow considerations.
Coding & AlgorithmsOnsite - SpokeoMediumData ScientistAnswer Statistics Questions for Spokeo DS Role Quiz
This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Answer Statistics Questions for Spokeo DS Role Quiz states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - SpokeoMediumData ScientistSolve Logic Puzzles: Algorithms and Proofs Required
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Solve Logic Puzzles: Algorithms and Proofs Required states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnsite - StripeMediumData ScientistChoose target customers and define success metrics
This question tests the ability to design an experimental rollout strategy for a new financial product, requiring a balance between revenue growth, risk mitigation, and statistical validity.
Analytics & ExperimentationOnsiteExperimentationRisk ModelingProduct Analytics - StripeMediumData ScientistEvaluate Stripe Capital Lending Strategy
This question evaluates data science competencies in product analytics, credit risk modeling, monitoring and instrumentation for a merchant lending product, including dashboard metric design, early-warning signal engineering, offer-structuring trade-offs, and portfolio-level profit attribution.
Analytics & ExperimentationOnsite - StripeMediumData ScientistHow Should Stripe Capital Be Evaluated?
This problem tests your ability to design a performance measurement framework for a lending product, focusing on balancing merchant growth with credit risk.
Analytics & ExperimentationOnsiteCredit RiskProduct AnalyticsCohort Analysis - StripeMediumData ScientistResolve conflicts and prioritize with stakeholders
This question evaluates stakeholder management, prioritization frameworks, cross-functional conflict resolution, and decision documentation skills within a payments analytics context for a Data Scientist role.
Behavioral & LeadershipOnsite - StripeMediumData ScientistWrite SQL to monitor weekly chargeback spikes
This question evaluates proficiency in PostgreSQL time-series analytics, specifically aggregations, joins across payments and chargebacks, handling late-arriving events, and calculating per-week metrics such as GMV, active merchants, and chargeback rates.
Data Manipulation (SQL/Python)Onsite - ThumbtackMediumData ScientistCompare list/dict; parse JSON/CSV at scale
This question evaluates understanding of Python data structures (list vs dict), algorithmic time and memory complexity, ordering guarantees in CPython, large-scale parsing and streaming of JSON/CSV, and robust data-cleaning and error-handling strategies.
Data Manipulation (SQL/Python)Onsite - ThumbtackMediumData ScientistCompute weighted response rates by job category
This question evaluates a candidate's data manipulation and statistical estimation skills, including pandas-based aggregation, invitation-weighted rate calculation, confidence-interval computation, and robust handling of data-quality issues, in the Data Manipulation (SQL/Python) domain.
Data Manipulation (SQL/Python)Onsite