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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
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- 11
- Topics
- 8
- Languages
Showing 481–510 of 1076 results
- HuluMediumData ScientistDesign and Monitor a Multi-Country Parameter Experiment
This question tests the ability to design an A/B test across multiple regions while accounting for sample size requirements, variance reduction techniques, and sequential monitoring protocols.
Analytics & ExperimentationTechnical ScreenA/B TestingPower AnalysisCUPED - HuluMediumData ScientistInterpret a Streaming Regression Without Overstating Causality
This problem tests your ability to interpret multivariate regression results for product stakeholders, specifically focusing on distinguishing correlation from causation and identifying risks like collider bias.
Analytics & ExperimentationTechnical ScreenRegressionCausal InferenceExperimental Design - IBMEasyData ScientistDesign a lead-scoring model
Design an end-to-end lead-scoring model for a marketing/growth data science team: define the label and scoring time, engineer leakage-safe features, compare a logistic-regression baseline with gradient-boosted trees, and evaluate with capacity-aware ranking metrics. The question also probes multicollinearity, model interpretability (SHAP/reason codes), routing-threshold design, and operational risks like selection bias, class imbalance, fairness, and drift.
Machine LearningTechnical Screen - IBMEasyData ScientistEstimate free-trial conversion probability
This question evaluates a data scientist's competency in cohort definition, censored-data handling, segmentation and confounding assessment, and uncertainty quantification for measuring free-trial to paid conversion, and it belongs to the Analytics & Experimentation domain within data science.
Analytics & ExperimentationTechnical Screen - IBMEasyData ScientistHow do you detect and fix multicollinearity?
This question evaluates understanding of multicollinearity and related competencies in regression diagnostics, feature engineering, model interpretability, and the trade-offs between coefficient inference and predictive performance.
Statistics & MathTechnical Screen - ImcEasyData ScientistFind valid range of q for outcome probabilities
This question tests the ability to solve a system of linear inequalities derived from probability constraints, requiring an understanding of basic arbitrage-free pricing principles.
Software Engineering FundamentalsTechnical ScreenProbabilityInequalitiesFinance - InstacartMediumData ScientistAggregate weekly revenue and attribute 4% drop
This question evaluates a candidate's ability to perform time-based revenue aggregation, filtering, percent-change calculation, and geo-level attribution using SQL or Python, with attention to ISO-week alignment and revenue computation.
Data Manipulation (SQL/Python)Technical Screen - InstacartMediumData ScientistCalculate Weekly Revenue and Order Count for Standard Deliveries
This question evaluates proficiency in time-based aggregations and filtering on order-level transactional data to compute weekly revenue and order counts specifically for standard delivery orders.
Data Manipulation (SQL/Python)Technical Screen - InstacartEasyData ScientistDesign a pricing experiment with network effects
This question evaluates experimental design and causal inference competencies for a two-sided marketplace pricing change, including handling network effects/interference, choice of unit of randomization and treatment markets, metric selection and diagnostics, power/MDE estimation, and operational risk assessment within the Analytics & Experimentation domain for a Data Scientist role. It is commonly asked to assess practical application of randomized and quasi-experimental methods across heterogeneous geographies and operational constraints, requiring both hands-on experimental design skills and conceptual understanding of bias, spillovers, and diagnostic metrics.
Analytics & ExperimentationTechnical Screen - InstacartEasyData ScientistHow to debug an apparent D14 retention drop
This question evaluates competency in cohort-based retention analysis, understanding metric maturity and right-censoring, performing data quality and definition checks, and localizing real declines across segments, releases, or funnel changes.
Analytics & ExperimentationTechnical Screen - InstacartEasyData ScientistHow would you investigate a metric decline?
This question evaluates a data scientist's competency in diagnostic analytics, metric instrumentation awareness, causal reasoning, and segmentation-driven problem localization for consumer marketplace KPIs.
Analytics & ExperimentationTechnical Screen - InstacartMediumData ScientistInvestigate Instacart Revenue Decline Using Weekly Data
Instacart analytics prompt on investigating a 4% weekly revenue decline, covering time-series anomaly detection, seasonality, changepoints, prediction intervals, and richer-data decomposition by orders, AOV, geography, cohorts, and categories.
Analytics & ExperimentationTechnical Screen - InstacartEasyData ScientistInvestigate marketplace metrics and experiment rollout
This question evaluates competency in marketplace analytics, causal inference, experimentation design, metric instrumentation, cohort and retention analysis, and trade-off reasoning between core business metrics and secondary signals.
Analytics & ExperimentationTechnical Screen - InstacartMediumData ScientistRecommend and validate a budget allocation strategy
This question evaluates a data scientist's competency in budget allocation, experimental design, KPI definition, segmentation, and causal inference by requiring translation of SQL-derived spend and profitability insights into constrained program- and advertiser-level budget rules while managing concentration risk.
Analytics & ExperimentationTechnical Screen - InstacartMediumData ScientistWrite SQL to rank advertisers and profitability
This question evaluates a candidate's ability to perform ANSI SQL data transformations including unpivoting denormalized tables, aggregations, joins, and financial metric calculations such as net profit and profit margin while handling nulls and tie-breaking rules.
Data Manipulation (SQL/Python)Technical Screen - Intercontinental ExchangeMediumData ScientistAnalyze Newton-Raphson Convergence, Choose Sigma, and Derive Vega
This question evaluates numerical root-finding and option pricing competencies, specifically understanding Newton–Raphson convergence properties, implied volatility inference under the Black–Scholes model, and option sensitivity (Vega).
Statistics & MathTechnical Screen - IntuitMediumData ScientistBuild 30-day retention cohort table
This problem tests your ability to aggregate user activity data to calculate 30-day retention rates, requiring joins, date arithmetic, and windowing functions.
Analytics & ExperimentationTechnical ScreenSQLRetentionCohort Analysis - IntuitMediumData ScientistBuild cohort 30-day retention from signup date
This problem tests your ability to manipulate time-series data to calculate cohort-based user retention rates while handling data censoring constraints.
Analytics & ExperimentationTechnical ScreenSQLPandasRetention - IntuitMediumData ScientistCompute monthly new subscribers and YoY deltas
This question evaluates proficiency in SQL time-series aggregation and cohort identification, including generating a month spine, computing year-over-year deltas, handling nulls and division-by-zero, and identifying partial months via a data watermark.
Data Manipulation (SQL/Python)Technical Screen - IntuitEasyData ScientistDesign an experiment for pricing page redesign
This question evaluates a candidate's competency in experiment design, causal inference, impact sizing, metric framework development, and statistical analysis in the context of a pricing page redesign that adds an annual subscription option.
Analytics & ExperimentationTechnical Screen - IntuitMediumData ScientistEngineer and Impute ZIP Features
This Intuit data scientist machine learning screen evaluates feature engineering from address/ZIP data, joining external census-style datasets, high-cardinality encoding, and missing-ZIP imputation. It also tests awareness of fairness, privacy, leakage, and how to validate whether geographic features actually improve a model.
Machine LearningTechnical Screen - IntuitMediumData ScientistExclude free subscribers via anti-join
This question evaluates competency with SQL anti-joins, join semantics, deduplication, and correct pre-aggregation filtering to prevent excluded entities from affecting aggregated monthly and year-over-year metrics; it is categorized as Data Manipulation (SQL/Python) for a Data Scientist role.
Data Manipulation (SQL/Python)Technical Screen - IntuitEasyData ScientistPivot daily users and revenue by platform
This question evaluates data manipulation and aggregation skills, specifically computing distinct user counts and revenue aggregates and reshaping results by platform; it is in the Data Manipulation (SQL/Python) domain and assesses practical application rather than purely conceptual understanding.
Data Manipulation (SQL/Python)Technical Screen - J.P. MorganEasyData ScientistCompute expected value of simple gambling games
This problem tests your understanding of expected value, probability distributions, and the mechanics of independent trials in simple gambling games.
Software Engineering FundamentalsTechnical ScreenProbabilityStatisticsExpected Value - J.P. MorganMediumData ScientistExplain Overfitting and Transformer Basics
This question tests your conceptual understanding of model generalization, the mechanics of the Transformer architecture, and the trade-offs involved in sequence modeling.
Machine LearningTechnical ScreenDeep LearningTransformersBias-Variance Tradeoff - J.P. MorganMediumData ScientistImplement Integer Square Root
This question evaluates numerical algorithm design and integer arithmetic competence, including robustness for edge cases and overflow handling, and is categorized in the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - J.P. MorganMediumData ScientistImplement KNN from Scratch
This problem tests your ability to implement the K-Nearest Neighbors (KNN) algorithm from scratch, focusing on distance computation, sorting, and majority voting logic.
Coding & AlgorithmsTechnical ScreenKNNSupervised LearningAlgorithms - Jain GlobalEasyData ScientistDefine the p-Value, Then Explain How to Test Two Price Series for Cointegration
Two statistics questions from a systematic trading screen: give a precise definition of the p-value and its common misreadings, then explain what cointegration is and how to test two price series for it. It tests hypothesis-testing rigor, stationarity, the difference between correlation and cointegration, and multiple-testing pitfalls.
Statistics & MathTechnical Screen - JefferiesEasyData ScientistHow to compute correlation from variances
Practice deriving correlation from variance identities for two random variables. The solution explains why Var(X+Y) and Var(X) alone are insufficient, derives covariance and correlation when Var(Y) is known, simplifies the equal-variance case, and checks edge cases where correlation is invalid or inconsistent.
Statistics & MathTechnical Screen - JefferiesMediumData ScientistHow to derive correlation from variances
Evaluates derivation of correlation from variance identities for two random variables. Strong answers explain why Var(X+Y) and Var(X) alone do not identify correlation, then derive covariance and correlation when Var(Y) is also known.
Statistics & MathTechnical Screen