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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.

9403
Questions
546
Companies
11
Topics
8
Languages

Showing 541–570 of 641 results

  • RobinhoodMediumData Scientist
    Design 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 Scientist
    Design 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 Scientist
    Analyze 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 Scientist
    Defend 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 Scientist
    Generate 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 Scientist
    Match 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 Scientist
    Optimize 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 Scientist
    Analyze 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 Scientist
    Assess 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 Scientist
    Calculate 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 Scientist
    Determine 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 Scientist
    Diagnose 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 Scientist
    Measure 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 Scientist
    Compute 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 Scientist
    Compute 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 Scientist
    Design 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 Scientist
    How 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 Scientist
    Influence 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 Scientist
    Build 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 Scientist
    Design 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 Scientist
    Solve 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 Scientist
    Answer 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 Scientist
    Solve 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 Scientist
    Choose 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 Scientist
    Evaluate 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 Scientist
    How 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 Scientist
    Resolve 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 Scientist
    Write 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 Scientist
    Compare 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 Scientist
    Compute 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