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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.
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Showing 1–30 of 104 results
- AdobeEasyData ScientistUnderstand P-Value's Role in Product Decision-Making
This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Understand P-Value's Role in Product Decision-Making states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - AmazonMediumData ScientistCalculate A/B sample size, CI, decision rules
This question evaluates skills in experimental design and statistical inference, including sample size calculation, hypothesis testing, confidence interval interpretation, multiple comparison control, variance reduction techniques, and operational considerations for A/B testing.
Statistics & MathOnsite - AmazonHardData ScientistEstimate Treatment Effects Using PSM, DiD, and DML Methods
Estimate Treatment Effects Using PSM, DiD, and DML Methods 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 - AmazonMediumData ScientistIdentify P-Value Limitations and Complementary Approaches
Identify P-Value Limitations and Complementary Approaches 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 - AppleMediumData ScientistDifferentiate P-value and Confidence Interval in Statistics
This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Differentiate P-value and Confidence Interval in Statistics states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - Capital OneEasyData ScientistCompute Optimal Die Re-roll Strategy
This question tests the ability to calculate expected values and determine optimal decision thresholds in a multi-stage probabilistic game.
Statistics & MathOnsiteProbabilityExpected ValueDecision Theory - Capital OneMediumData ScientistCompute credit-card portfolio profit and breakeven
This question evaluates financial modeling, unit-economics calculation, breakeven analysis, and basic risk/expected-loss estimation relevant to a Data Scientist, testing competency in statistics & math and algebraic derivation within financial analysis.
Statistics & MathOnsite - Capital OneMediumData ScientistCompute expansion profits and expected value
This question evaluates financial modeling, expected-value decision-making, probability reasoning, and sensitivity analysis skills applied to revenue, variable and fixed cost interactions and contractual fee impacts, aimed at a Data Scientist role.
Statistics & MathOnsite - Capital OneMediumData ScientistDetermine Claim Rate for Breakeven in Insurance Portfolio
Evaluates weather-insurance portfolio profitability from premiums, servicing, regulatory costs, and expected claims. Strong answers derive break-even claim rate, segment-selection rules, and incremental profit formulas.
Statistics & MathOnsite - Capital OneHardData ScientistDiagnose and fix a flight-delay modeling setup
This question evaluates proficiency in statistical modeling for binary outcomes, including concepts such as appropriate model choice and link functions, categorical encoding, ETL-driven data quality issues, multicollinearity diagnostics (e.g.
Statistics & MathOnsite - Capital OneMediumData ScientistEstimate Default Rates Using Logistic Regression Model
This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Estimate Default Rates Using Logistic Regression Model states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - Capital OneMediumData ScientistInterpret regression metrics and assumptions
This question evaluates a candidate's mastery of multiple linear regression diagnostics and interpretation, covering standardized coefficient interpretation and significance, R²/adjusted R² and out‑of‑fold RMSE comparisons, multicollinearity detection and its effect on coefficients and SEs, heteroskedasticity diagnostics and robust remedies, and implications of intercept omission and partial standardization. Commonly asked in data scientist interviews within the Statistics & Math domain because it probes both conceptual understanding of statistical inference and practical application of model diagnostics and adjustments for reliable prediction and inference.
Statistics & MathOnsite - Capital OneMediumData ScientistModel network-service unit economics and breakeven
This question evaluates a data scientist's ability to model unit economics, calculate per-customer contribution and breakeven, and conduct sensitivity and probabilistic churn analysis.
Statistics & MathOnsite - Capital OneMediumData ScientistQuantify and Model Flight Delays Using Statistical Tests
Evaluates flight-delay quantification, modeling, and mitigation testing using historical operational data. Strong answers define delay metrics, model delay probability and severity, avoid leakage, and design valid experiments.
Statistics & MathOnsite - CitadelHardData ScientistSolve Classic Probability Questions
This problem tests your ability to calculate the expected stopping time of a stochastic process and your proficiency with the linearity of expectation in the context of sequential probability.
Statistics & MathOnsiteProbabilityExpectationStochastic Processes - CitadelHardData ScientistSolve probability and expectation problems
This set of problems evaluates probabilistic reasoning and expectation skills across discrete and continuous settings, covering conditional probability with evolving information, convolution and distribution derivation, occupancy/collector problems, symmetry-based variance on manifolds, and sequential selection/optimal stopping.
Statistics & MathOnsite - CoinbaseMediumData ScientistCalculate Conversion Lift CI
This question tests the ability to derive and calculate a confidence interval for the difference in conversion rates between two groups, and to explain how this interval informs a business decision.
Statistics & MathOnsiteStatisticsA/B TestingInference - CoinbaseMediumData ScientistCalculate a Confidence Interval
This question evaluates a candidate's competency in statistical inference for A/B testing, specifically the construction and interpretation of confidence intervals for differences in proportions, and falls under the Statistics & Math domain relevant to Data Scientist roles; it tests practical application (deriving point estimates and standard errors) alongside conceptual understanding (assumptions behind normal approximation versus exact, score-based, or bootstrap intervals). Interviewers commonly ask this to assess ability to quantify treatment effects, reason about approximation validity and alternative interval methods, and distinguish between absolute and relative lift when reporting experimental results.
Statistics & MathOnsite - DRWMediumData ScientistCompute Markov steady state and expectations
Compute Markov steady state and expectations 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 - DRWEasyData ScientistDerive eigenvalues and sum for inverse matrix
Derive eigenvalues and sum for inverse matrix 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 - DRWMediumData ScientistSolve Markov and distribution expectation problems
This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Solve Markov and distribution expectation problems states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - DoorDashHardData ScientistDefine and compute retention and churn precisely
This question evaluates a Data Scientist's competency in statistical measurement of user retention and churn, covering cohort definition, activity rules, risk-set-aware retention and churn formulas, censoring and delayed conversion handling, and survival-analysis concepts like time-to-churn, hazard, and cumulative incidence.
Statistics & MathOnsite - GleanMediumData ScientistExpectation and Variance of a Sum of Two Random Variables, Including Covariance
Asks how to compute the expectation and variance of the sum of two random variables, in general and when they are independent. Tests derivation from definitions, the role of covariance, generalizing to weighted sums and differences, and applying the result to data-science problems such as comparing group means.
Statistics & MathOnsite - GleanEasyData ScientistWhat are sum expectation and variance?
This question evaluates understanding of expectation, variance and covariance and the ability to reason about how sums of random variables affect their moments, including the role of covariance and the special case of independence in the Statistics & Math domain.
Statistics & MathOnsite - GoogleMediumData ScientistCan bootstrap help reduce variance
This question evaluates understanding of bootstrap resampling, the distinction between estimating an estimator’s variance and methods that actually reduce estimator variance, and related ensemble reasoning for a Data Scientist role in the Statistics & Math domain.
Statistics & MathOnsite - GoogleHardData ScientistDesign human review to estimate model accuracy
This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Design human review to estimate model accuracy states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - GoogleHardData ScientistEstimate Population Mean and Conversion Rate Accurately
Evaluates core statistical inference skills across p-values, confidence intervals, standard error reduction, tail probability estimation, efficient conversion-rate sampling, and truncated-normal estimation. Strong answers state assumptions, use appropriate intervals and weights, and avoid common interpretation errors.
Statistics & MathOnsite - GoogleMediumData ScientistExplain P-values and Confidence Intervals in Simple Linear Regression
Review p-values, confidence intervals and slope inference in simple linear regression, including assumptions and causal limits.
Statistics & MathOnsite - GoogleEasyData ScientistExplain mixed models and fixed vs random effects
This question evaluates understanding of mixed effects models, the conceptual distinction between fixed and random effects, interpretation of coefficients and variance components, and awareness of practical pitfalls when modeling hierarchical or panel data.
Statistics & MathOnsite - GoogleMediumData ScientistInterpreting a Dosage-Recovery Regression: P-values, CIs, Causality
Given a fitted dosage-vs-recovery-time regression, explain exactly what the reported p-value and confidence interval mean, what assumptions back that inference, how a confidence interval differs from a prediction interval, and why the result alone cannot establish causality. Tests statistical precision under pressure.
Statistics & MathOnsitestatisticslinear-regressionhypothesis-testing