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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 151–180 of 1971 results

  • AmazonMediumData Scientist
    Implement a high-throughput web crawler safely

    This question evaluates competency in concurrent systems, scalable data ingestion, and algorithmic design for a high-throughput web crawler, covering URL normalization, deduplication, per-host rate limiting, fault-tolerant checkpointing, and bounded-memory queueing.

    Coding & AlgorithmsTechnical Screen
  • AmazonMediumData Scientist
    Implement and Analyze 'Merge k Sorted Lists' Algorithm

    This question evaluates algorithm design skills and complexity analysis for merging multiple sorted sequences, measuring proficiency with appropriate data structures, time-space trade-offs, and correctness reasoning.

    Coding & AlgorithmsOnsite
  • AmazonMediumData Scientist
    Implement list overlap and dense-ranked word frequencies

    This question evaluates a data scientist's ability to implement efficient multiset intersection and streaming top-k word-frequency computations, covering duplicate-aware counting, dense-ranking, Unicode handling, and strict time/space constraints.

    Coding & AlgorithmsOnsite
  • AmazonMediumData Scientist
    Implement streaming k-way merge with constraints

    This question evaluates competence in streaming algorithms and resource-constrained algorithm design, specifically implementing a k-way merge over blocking, potentially unbounded integer iterators while preserving stable duplicates and reasoning about time and O(k) space complexity.

    Coding & AlgorithmsOnsite
  • AmazonMediumData Scientist
    List Top Customers and Monthly Order Counts in SQL

    This question evaluates a candidate's ability to perform SQL aggregation, grouping, top‑N selection, and date-based summarization to compute customer spend and chronological monthly order counts.

    Data Manipulation (SQL/Python)Technical Screen
  • AmazonMediumData Scientist
    Mitigate Data Mistakes and Improve Team Efficiency

    This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Mitigate Data Mistakes and Improve Team Efficiency states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Behavioral & LeadershipTechnical Screen
  • AmazonMediumData Scientist
    Navigate Crises and Sustain Team Morale Under Pressure

    Navigate Crises and Sustain Team Morale Under Pressure evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Behavioral & LeadershipOnsite
  • AmazonMediumData Scientist
    Optimize Email Strategy for New Prime Video Series Launch

    Evaluates email targeting and ranking strategy for a new Prime Video series launch. Strong answers cover data needs, cold start, ranking models, offline metrics, A/B testing, guardrails, and model selection.

    Machine LearningOnsite
  • AmazonMediumData Scientist
    Optimize Predictive Analytics: Feature Engineering to Model Evaluation

    Evaluates end-to-end predictive analytics project communication for a technical data-science interview. Strong answers cover business objectives, data, leakage controls, features, models, evaluation, errors, and impact.

    Machine LearningTechnical Screen
  • AmazonMediumData Scientist
    Optimize XGBoost for Predicting Marketing Outcomes

    Optimize XGBoost for Predicting Marketing Outcomes evaluates core ML concepts, assumptions, math intuition, training/evaluation trade-offs, and practical failure modes in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Machine LearningOnsite
  • AmazonHardData Scientist
    Plan and analyze an A/B test

    This question tests the ability to design a statistically rigorous A/B test by accounting for clustered randomization, sequential testing boundaries, and multiple comparison corrections.

    Statistics & MathTechnical ScreenExperimental DesignPower AnalysisClustered Data
  • AmazonMediumData Scientist
    Prioritize Tasks and Respond to Coworker Concerns

    This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Prioritize Tasks and Respond to Coworker Concerns states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Behavioral & LeadershipOnline Assessment
  • AmazonHardData Scientist
    Prioritize a new warehouse proposal with data

    This question evaluates demand forecasting, network optimization, five-year NPV financial modeling, experiment and quasi-experiment design for incrementality estimation, sensitivity analysis, and stakeholder communication within the analytics & experimentation domain for data science roles focused on warehouse/fulfillment center decisions.

    Analytics & ExperimentationTechnical Screen
  • AmazonMediumData Scientist
    Profile and visualize an unfamiliar dataset

    This question evaluates a data scientist's competency in exploratory data analysis, data quality assessment, time-series aggregation, visualization design, and concise stakeholder communication when working with an undocumented events-plus-purchases CSV.

    Analytics & ExperimentationTechnical Screen
  • AmazonHardData Scientist
    Quantify build-vs-buy training decision

    This question evaluates proficiency in quantitative decision analysis, causal inference for experimentation, KPI definition, and risk‑adjusted financial modeling within the Analytics & Experimentation domain, assessing skills relevant for a Data Scientist making operational trade‑offs.

    Analytics & ExperimentationOnline Assessment
  • AmazonMediumData Scientist
    Resolve Conflicts Between Data Findings and Team Opinions

    Resolve Conflicts Between Data Findings and Team Opinions evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Behavioral & LeadershipOnsite
  • AmazonMediumData Scientist
    Resolve Team Conflicts and Deliver Beyond Project Scope

    This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Resolve Team Conflicts and Deliver Beyond Project Scope states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Behavioral & LeadershipTechnical Screen
  • AmazonMediumData Scientist
    Resolve a team conflict decisively

    The question evaluates conflict-resolution, decisive leadership, stakeholder management, evidence-based decision-making, communication under time pressure, and the ability to enforce delivery timelines and run post-mortems within a Data Scientist role.

    Behavioral & LeadershipTechnical Screen
  • AmazonMediumData Scientist
    Respond to Difficult Critical Feedback

    Practice discussing difficult feedback with a concrete example, an observable behavior change, and evidence of improvement.

    Behavioral & LeadershipTechnical Screen
  • AmazonHardData Scientist
    Root-cause an incident and drive consensus

    This question evaluates root-cause analysis, incident management, cross-functional stakeholder coordination, and quantitative diagnostic reasoning in the context of a sudden drop in voice checkout conversion, testing product analytics, ML-driven user flows, and operational reliability within the Behavioral & Leadership category.

    Behavioral & LeadershipOnsite
  • AmazonMediumData Scientist
    Select Top Customers Using Transaction Data Filters

    This question evaluates a candidate's ability to perform data aggregation, filtering, ranking, and deterministic tie-breaking on transactional datasets, assessing skills in Data Manipulation (SQL/Python).

    Data Manipulation (SQL/Python)Technical Screen
  • AmazonMediumData Scientist
    Solve Algorithmic Challenges in Online Coding Assessments

    This question evaluates proficiency in fundamental algorithmic problem-solving, specifically array manipulation, string processing, and the use of basic data structures along with performance and complexity reasoning.

    Coding & AlgorithmsTechnical Screen
  • AmazonMediumData Scientist
    Solve Search Insert Position Using Binary Search

    This question evaluates proficiency in binary search, algorithmic implementation on sorted arrays, and understanding of time complexity and index management.

    Coding & AlgorithmsTechnical Screen
  • AmazonMediumData Scientist
    Solve stock, BFS path, and merge intervals

    This question evaluates algorithmic problem solving across array scanning, BFS-based constrained shortest-path selection, and interval merging, with emphasis on time/space complexity reasoning, correctness proofs, and thorough edge-case handling. It is commonly asked to assess efficiency guarantees (e.g.

    Coding & AlgorithmsTechnical Screen
  • AmazonHardData Scientist
    Solve subset-count and kth-factor problems

    This question evaluates algorithm design and analysis skills, including selection under sum constraints with negatives and zeros, streaming and query-preprocessing strategies for repeated budgets, and number-theoretic factor enumeration for large N, all within the Coding & Algorithms domain.

    Coding & AlgorithmsOnline Assessment
  • AmazonEasyData Scientist
    Solve two string DP/hash problems

    This question set evaluates string-processing and algorithmic problem-solving skills, including encoding and transformation for unique representations and dynamic programming, memoization, and backtracking for enumerating all valid segmentations.

    Coding & AlgorithmsTechnical Screen
  • AmazonMediumData Scientist
    Solve two-sum variants at scale

    This question evaluates array and hashing algorithms, pair-sum reasoning including duplicate handling and lexicographic minimality, streaming and external-memory algorithm design, trade-offs in time/space complexity, and extension to three-sum with deduplication.

    Coding & AlgorithmsOnsite
  • AmazonMediumData Scientist
    Transform Customer Feedback into Valuable Product Enhancements

    Transform Customer Feedback into Valuable Product Enhancements evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Behavioral & LeadershipOnsite
  • AmazonMediumData Scientist
    Transform event logs with subscription windows in pandas

    This question evaluates a candidate's competency in time-based event attribution and temporal interval manipulation using pandas, covering interval merging, subscription-aligned revenue aggregation, anomaly flagging, and handling edge cases like overlapping or back-to-back subscriptions.

    Data Manipulation (SQL/Python)Onsite
  • AmazonMediumData Scientist
    Understand SQL: DELETE vs TRUNCATE, VIEW vs TABLE, CROSS JOIN

    This question evaluates a candidate's understanding of core SQL concepts and data-manipulation competencies, covering the behavior of data-deletion operations, distinctions between logical and physical data structures, and join semantics.

    Data Manipulation (SQL/Python)Technical Screen