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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 1621–1650 of 1971 results

  • SnowflakeMediumData Scientist
    Lead innovation and automate a critical process

    This question evaluates leadership and technical program management competencies for a Data Scientist, including end-to-end innovation, cross-functional stakeholder alignment, risk identification and mitigation, trade-off rationale, measurable impact assessment, and process automation architecture and maintainability.

    Behavioral & LeadershipTechnical Screen
  • SnowflakeMediumData Scientist
    Query seven-day conversion with windows and dedupe

    This question evaluates proficiency in time-windowed aggregations, event deduplication, and window-function–based user-level analytics across SQL and Pandas workflows.

    Data Manipulation (SQL/Python)Technical Screen
  • 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
  • SoFiMediumData Scientist
    Align with PM on ranking goals

    This question evaluates stakeholder alignment, risk management, product-ranking trade-offs, regulatory and compliance awareness, metric definition, and communication and negotiation skills relevant to delivering an MVP while planning a future ML iteration.

    Behavioral & LeadershipTechnical Screen
  • SoFiHardData Scientist
    Plan and validate ranking experiment

    This question evaluates skills in experimental design and analytics, covering offline counterfactual replay, interleaving and A/B testing, sample-size and power computation, sequential testing and alpha spending, guardrail monitoring and ramp policies, proxy metrics and covariate adjustment, heterogeneous treatment effect analysis, and governance concerns such as p-hacking and Simpson’s paradox within the Analytics & Experimentation domain for Data Scientist roles. It is commonly asked to probe proficiency in rigorously validating ranking changes while balancing statistical error, operational risk and bias mitigation, and it emphasizes practical application of applied statistical concepts and experiment governance rather than purely theoretical understanding.

    Analytics & ExperimentationTechnical Screen
  • 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
  • SquarepointHardData Scientist
    Analyze expectations, correlations, and investment strategies

    This problem tests your understanding of stochastic processes in finance, the linear algebraic requirements for covariance matrices, and optimal decision-making under uncertainty.

    Machine LearningTechnical ScreenProbabilityLinear AlgebraStochastic Calculus
  • SquarepointMediumData Scientist
    Compare Bonds, Common Equity, and Dividend Payments

    Compare debt and common equity claims, cash flows, risks, and why company profits do not guarantee common-share dividends.

    Statistics & MathTechnical Screen
  • SquarepointMediumData Scientist
    Compare Winning Chances in a Card Game That Replays Ties

    Use symmetry and tied-round replay to compare two players drawing cards without replacement and derive the game's eventual winning probabilities.

    Statistics & MathTechnical Screen
  • SquarepointMediumData Scientist
    Compute drawdown, profit, and coin change

    This question evaluates a candidate's ability to compute financial time-series metrics and apply algorithmic techniques such as array processing and optimization/dynamic programming to identify maximum drawdown and its indices.

    Coding & AlgorithmsTechnical Screen
  • SquarepointMediumData Scientist
    Count Index Triplets With an Even Product Modulo a Given Number

    From a Squarepoint technical screen: count the triplets of distinct positions in an integer array whose three values have an even product, and return the count modulo a given number. It tests efficient counting on large inputs, parity with zero and negative values, and remembering to apply the required modulo.

    Coding & AlgorithmsTechnical Screen
  • SquarepointMediumData Scientist
    Count Ways to Reach Step n With a Given Set of Step Sizes

    From a Squarepoint technical screen: count the ordered sequences of moves that climb exactly n stairs when every move uses a step size from a given set. It tests careful counting of ordered choices, targets that cannot be reached, and the interviewer's follow-up about reducing the extra space the solution uses.

    Coding & AlgorithmsTechnical Screen
  • SquarepointMediumData Scientist
    Estimate Market Beta from Aligned Asset and Benchmark Returns

    Define market beta, identify the benchmark data needed beyond a stock's returns, and explain regression estimation and uncertainty.

    Statistics & MathTechnical Screen
  • SquarepointMediumData Scientist
    Explain Linear Regression Assumptions, Evaluation, and Feature Addition

    Explain least-squares regression, inference assumptions, evaluation metrics, and why added features affect training and test R-squared differently.

    Machine LearningTechnical Screen
  • SquarepointMediumData Scientist
    Explain derivatives, YTM, and core statistics

    This problem tests your understanding of fundamental financial math concepts (derivatives and YTM) and your ability to apply statistical rigor when modeling financial data.

    Statistics & MathTechnical ScreenFinanceStatisticsDerivatives
  • SquarepointMediumData Scientist
    Fewest Increment-All-but-One Moves to Make Array Values Equal

    From a Squarepoint technical screen: one move adds 1 to every element of an integer array except one chosen element, and you must find the fewest moves that make all elements equal. It tests reasoning about what each move really changes, along with negative values and answers beyond the 32-bit range.

    Coding & AlgorithmsTechnical Screen
  • SquarepointMediumData Scientist
    Find the Probability That Two Uniform Variables Have Product Above One-Half

    Compute the probability that two independent uniform variables have product above one-half by conditioning or integrating over the unit square.

    Statistics & MathTechnical Screen
  • SquarepointMediumData Scientist
    Implement drawdown, single-trade profit, coin change

    This question evaluates a candidate's algorithmic problem-solving skills across array and time-series processing, greedy optimization, and dynamic programming, requiring implementation and complexity analysis of maximum drawdown, single-trade profit, and coin change problems within the Coding & Algorithms domain for a Data Scientist role.

    Coding & AlgorithmsTechnical Screen
  • SquarepointHardData Scientist
    Maximize profit from one or many stock trades

    This question evaluates algorithmic problem-solving skills, particularly efficient array processing and profit-optimization across single-transaction and multiple-transaction variants, along with time and space complexity analysis.

    Coding & AlgorithmsTechnical Screen
  • SquarepointMediumData Scientist
    Maximize revenue from inventory sales

    This question evaluates algorithmic problem-solving and optimization competencies focused on dynamic resource allocation, revenue maximization, and designing efficient solutions that scale with large n, m, and quantities.

    Coding & AlgorithmsOnline Assessment
  • 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
    Choose threshold under costs and uncertainty

    This question evaluates cost-sensitive threshold selection, uncertainty quantification for expected profit, calibration diagnostics, and population drift detection in a data science setting.

    Statistics & MathTechnical Screen
  • StripeMediumData Scientist
    Compute power and interpret uplift metrics

    This question evaluates a Data Scientist's practical and conceptual competencies in A/B test design and analysis within the Statistics & Math domain, covering power/sample-size calculations, binary outcome inference, CUPED variance reduction, multiple-testing adjustments, and handling clustered/geographical data.

    Statistics & MathTechnical Screen
  • StripeHardData Scientist
    Design a leak-free time-split model

    This question evaluates a Data Scientist's competency in time-aware predictive modeling, including label leakage prevention for late-arriving events, temporal cross-validation, feature engineering, model selection (logistic regression vs gradient-boosted trees), calibration and thresholding for costed actions.

    Machine LearningTechnical Screen
  • StripeHardData Scientist
    Design a model for subscription adoption prediction

    This question evaluates a candidate's ability to design and productionize a supervised machine-learning pipeline for predicting subscription adoption, testing competencies in labeling strategy, leakage identification and prevention, feature engineering from transactional and merchant metadata, model selection and calibration, evaluation with time-based validation, and post-deployment monitoring. It is commonly asked in the Machine Learning domain for Data Scientist roles because it assesses practical application and production-ready design along with conceptual understanding of time-based splits, class imbalance, performance metrics, and drift detection.

    Machine LearningOnline Assessment
  • StripeHardData Scientist
    Design a target‑user prediction system

    This question evaluates skills in temporal label definition and leakage prevention, time‑bounded feature engineering (recency/frequency and content affinity), uplift and incremental effect estimation, model selection under class imbalance and budgeted outreach, offline metric design, calibration, fairness constraints, and production validation and monitoring. Common in Machine Learning/Data Science interviews, it is asked to gauge both conceptual understanding of causal and validation issues and practical application skills for deploying a ranked outreach model under capacity constraints, including appropriate cross‑validation and thresholding to map predictive scores to business outcomes.

    Machine LearningTechnical Screen
  • StripeMediumData Scientist
    Design an idempotent SQL ETL for late data

    This question evaluates practical skills in idempotent ETL design, deduplication by natural keys, handling late-arriving and out-of-order records, upsert/merge strategies, and SQL-based aggregation for daily metrics.

    Data Manipulation (SQL/Python)Technical Screen
  • StripeHardData Scientist
    Design and power an A/B test

    This question evaluates a data scientist's competency in experimentation design, including metrics selection and guardrails, statistical power and sample-size calculation, sequential monitoring and ramp strategies, operational checks for randomization and contamination, and choosing credible quasi-experimental alternatives.

    Analytics & ExperimentationTechnical Screen
  • StripeMediumData Scientist
    Design metrics and write SQL for a case

    This question evaluates the ability to define time‑bounded, attributable conversion metrics and to implement joins, aggregations, and diagnostic checks in SQL to measure marketing outreach impact.

    Data Manipulation (SQL/Python)Technical Screen