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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
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- 546
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- 11
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- 8
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Showing 121–150 of 1076 results
- AttentiveHardData ScientistExplain switch to product analytics and company fit
This question evaluates a data scientist's product analytics and leadership competencies, including end-to-end decision ownership, prioritization of product metrics, communicating trade-offs between statistical rigor and speed, and influencing stakeholders within a B2B mobile messaging context that has compliance and deliverability constraints.
Behavioral & LeadershipTechnical Screen - Auction.ComMediumData ScientistPresent a Clear Data Science Career Narrative
This question tests your ability to synthesize your past data science experiences into a cohesive, goal-oriented narrative that aligns with the specific requirements of a data-driven organization.
Behavioral & LeadershipTechnical ScreenBehavioralCommunicationStorytelling - Bank of AmericaMediumData ScientistDescribe initiative, project, analysis, and relationship-building
This set of behavioral and leadership questions evaluates initiative, quantitative and technical project execution, complex problem-solving, and relationship-building competencies relevant to a Data Scientist role within the Behavioral & Leadership domain.
Behavioral & LeadershipTechnical Screen - Bank of AmericaMediumData ScientistDiscuss a Recent Financial-Market Trend
Tests your ability to formulate and rigorously analyze a recent financial-market trend by decomposing asset value changes versus net organic investor flows, designing econometric hypothesis tests, and evaluating data limitations.
Analytics & ExperimentationTechnical ScreenFinancial AnalyticsTime SeriesHypothesis Testing - Bank of AmericaMediumData ScientistExplain core probability and ML statistics concepts
This question evaluates core probability and machine learning statistics competencies including probability basics, descriptive statistics, correlation versus independence, linear regression and regularization, and dimensionality reduction (PCA), falling under the Machine Learning domain for Data Scientist roles and testing both conceptual understanding and practical application. Such multi-part theory questions are commonly asked to probe understanding of fundamental statistical concepts and modeling assumptions, ensuring the candidate can reason about uncertainty, estimator properties, multicollinearity, and eigenstructure without relying solely on implementation details.
Machine LearningTechnical Screen - Bank of AmericaMediumData ScientistShow Initiative, Analytical Judgment, and Relationship Building
This question assesses a candidate's ability to articulate professional narratives that demonstrate self-driven impact, rigorous problem-solving, and interpersonal collaboration skills.
Behavioral & LeadershipTechnical ScreenBehavioralCommunicationProblem-solving - BetterHelpMediumData ScientistDescribe Your Most Challenging Data Project Experience
This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Describe Your Most Challenging Data Project Experience states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipTechnical Screen - BetterHelpHardData ScientistOptimize Experiment Thresholds for Impactful Feature Launches
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 Optimize Experiment Thresholds for Impactful Feature Launches states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Analytics & ExperimentationTechnical Screen - BlackEdgeEasyData ScientistSolve quantitative word and algebra problems
This question evaluates quantitative reasoning and arithmetic/algebraic manipulation, covering unit conversion, percentage change, systems of linear equations, time-rate calculations, and series/summation properties.
Statistics & MathTechnical Screen - BlackRockEasyData ScientistDescribe a quantitative market model you built
A BlackRock Data Scientist technical-screen question in three parts: describe a quantitative market-data model (problem, data, methodology, validation, and assumptions/failure modes), explain how you transfer quantitative reasoning to other domains, and give a balanced perspective on the future of quantitative finance. The answer supplies a reusable five-part framework, a worked factor-model example, cross-domain mappings, and the rubric interviewers actually score.
Behavioral & LeadershipTechnical Screen - BlackRockMediumData ScientistDiscuss the future of quantitative finance
This question evaluates strategic, domain-level understanding of quantitative finance, including macroeconomic role, trend identification, risk dynamics, regulatory considerations, and technology impacts as relevant to a Data Scientist role.
Behavioral & LeadershipTechnical Screen - Block (Square)MediumData ScientistBuild referral chains and detect cycles
This question evaluates graph algorithm competencies such as referral-chain traversal, cycle detection, handling noisy input data, and reasoning about time and space complexity for efficient per-node computation.
Coding & AlgorithmsTechnical Screen - Block (Square)MediumData ScientistWrite left-join queries with tricky filters
This question evaluates SQL data-manipulation skills including LEFT JOIN semantics, aggregation functions like COUNT(DISTINCT) and SUM, GROUP BY/HAVING logic, and date-window filtering for referral and order analytics.
Data Manipulation (SQL/Python)Technical Screen - BnpEasyData ScientistExplain and compute option delta
Evaluates understanding of option delta, the differing intuitions/signs for calls versus puts, and the ability to compute deltas under the Black–Scholes model; commonly asked to assess quantitative reasoning about derivative sensitivities, model-based pricing, and hedging concepts.
Software Engineering FundamentalsTechnical Screen - BnpEasyData ScientistFind expected tosses to see a coin pattern
Assesses probabilistic reasoning and stochastic-process modeling skills, focusing on expected stopping times for pattern occurrences in repeated independent trials and related concepts like state-space representation and overlap effects.
Software Engineering FundamentalsTechnical Screen - BnpEasyData ScientistHow do you split coins to match heads?
This question evaluates logical reasoning about invariants and combinatorial parity, testing the candidate's ability to design deterministic strategies under partial information; it falls under Software Engineering Fundamentals with relevance to probability and discrete mathematics for a Data Scientist role.
Software Engineering FundamentalsTechnical Screen - BnpEasyData ScientistWhat are linear regression assumptions?
Assesses understanding of the assumptions underlying ordinary least squares linear regression and the application of diagnostic methods to ensure unbiased parameter estimates and valid statistical inference.
Machine LearningTechnical Screen - Boston Consulting GroupMediumData ScientistAnalyze Python Functions: Improve Readability and Efficiency
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Analyze Python Functions: Improve Readability and Efficiency states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsTechnical Screen - Boston Consulting GroupMediumData ScientistDesign and sample for credit default prediction
This question evaluates a data scientist's competencies in imbalanced binary classification, temporal label definition and leakage detection, sampling and calibration under prior-probability shift, metric and operating-point selection, cost-sensitive decision rules, time-based validation and monitoring, and fairness and operational guardrails.
Machine LearningTechnical Screen - Boston Consulting GroupMediumData ScientistIdentify Causes and Solutions for Fashion Profit Decline
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 Identify Causes and Solutions for Fashion Profit Decline states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Analytics & ExperimentationTechnical Screen - Boston Consulting GroupMediumData ScientistManipulate and merge DataFrames correctly
This question evaluates proficiency in pandas-based data manipulation and merging, covering join validation, vectorized revenue and discount calculations, missing-value imputation, groupby/transform usage, dtype setting, and avoiding SettingWithCopy issues.
Data Manipulation (SQL/Python)Technical Screen - Boston Consulting GroupMediumData ScientistQuery top spenders and 7-day growth
This question evaluates proficiency in SQL data manipulation, including aggregations, date-range filtering, joins, window functions for ranking and tie-breaking, and computing revenue shares and growth rates within a relational schema.
Data Manipulation (SQL/Python)Technical Screen - Boston Consulting GroupHardData ScientistReduce overfitting under constraints
This question evaluates a candidate's competency in machine learning for mitigating overfitting in tabular regression under production latency constraints, testing knowledge of regularization, model complexity control, feature engineering, validation strategies, and experimental design.
Machine LearningTechnical Screen - Boston Consulting GroupMediumData ScientistSummarize impact and lessons from your resume
This question evaluates a data scientist's ability to communicate measurable impact, design and track metrics, manage stakeholders and conflicts, and demonstrate accountability through concrete project examples, testing Behavioral & Leadership competencies specific to the Data Scientist role.
Behavioral & LeadershipTechnical Screen - Boston Consulting GroupMediumData ScientistTransform messy transactions with pandas
This question evaluates proficiency in large-scale data manipulation and feature engineering using pandas, covering timestamp normalization across time zones, deduplication and last-write-wins semantics, data validation, memory-efficient aggregation, rolling-window statistics, and top-k categorical extraction for merchant categories.
Data Manipulation (SQL/Python)Technical Screen - Boston Consulting GroupMediumData ScientistVisualize and Clean SKU Sales Data for Outliers
This question evaluates data manipulation and exploratory data analysis skills, including aggregation, outlier detection (IQR/Z-score) and visualization using Python libraries such as pandas and matplotlib/seaborn.
Data Manipulation (SQL/Python)Technical Screen - ByteDanceMediumData ScientistCalculate Triangle Probability From Broken Stick
This question evaluates a candidate's understanding of geometric probability, continuous random variables, and spatial reasoning within probabilistic models.
Statistics & MathTechnical Screen - ByteDanceMediumData ScientistCampaign Efficiency Metrics and Below-Average CTR
Practice a data scientist SQL interview question that calculates campaign cost and funnel rates, handles zero denominators, and filters campaigns against an average CTR benchmark. The exercise tests PostgreSQL date arithmetic, CTE organization, NULL-safe calculations, and deterministic output.
Data Manipulation (SQL/Python)Technical Screen - ByteDanceMediumData ScientistChoose Ranking Functions, Customer Value Metrics, and Predictive Models
This problem tests the ability to implement SQL window functions for cohort analysis, define robust customer lifetime value metrics, and articulate the trade-offs between various machine learning algorithms in a production setting.
Machine LearningTechnical ScreenSQLCustomer-AnalyticsModel-Selection - ByteDanceMediumData ScientistCompare SQL counts, windows, and NULL semantics
This question evaluates understanding of SQL aggregation and NULL semantics, window functions (ROW_NUMBER vs RANK), join behavior to avoid double-counting, and defensive handling of NULLs and divide-by-zero using COALESCE and NULLIF in a data manipulation context.
Data Manipulation (SQL/Python)Technical Screen