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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 271–300 of 344 results
- SIG (Susquehanna)EasyData ScientistSolve animals-and-legs count
This question evaluates a candidate's ability to translate a word problem into a system of linear equations and perform basic algebraic manipulation and arithmetic to determine unknown quantities.
Statistics & MathOnline Assessment - SIG (Susquehanna)MediumData ScientistSolve relative-truth cat puzzle
This question evaluates logical deduction, constraint satisfaction, and quantitative manipulation of percentages and averages within a relative truth/lie framework, and is categorized under Statistics & Math and discrete logic puzzles.
Statistics & MathOnline Assessment - SIG (Susquehanna)EasyData ScientistUse Bayes for factory identification
This question evaluates understanding of Bayesian inference and conditional probability by asking for the posterior probability that two observed black widgets originated from a specific factory.
Statistics & MathOnline Assessment - SamsungMediumData ScientistEstimate laptops in an office
This question evaluates back-of-the-envelope estimation skills, quantitative reasoning, and the ability to state and justify assumptions when modeling real-world counts like devices.
Statistics & MathHR Screen - ShopifyMediumData ScientistPerform no-calculator math accurately and fast
This question evaluates mental arithmetic, rapid estimation, numerical bounds, and familiarity with exponentials and square-root approximations within the Statistics & Math category for a Data Scientist role.
Statistics & MathTechnical Screen - SnapchatMediumData ScientistAnalyze OLS After Duplicating Every Observation
This question tests your understanding of OLS coefficient estimation and standard error calculations under the scenario of duplicate data observations.
Statistics & MathTechnical ScreenOLSLinear RegressionStatistics - SnapchatMediumData ScientistDiagnose Violations of Linear Regression Assumptions
Tests a candidate's systematic understanding of ordinary least squares (OLS) regression assumptions, distinguishing how specific violations compromise unbiased point estimation, standard error inference, and predictive accuracy.
Statistics & MathTechnical ScreenStatisticsLinear RegressionEconometrics - SnapchatMediumData ScientistHow to Update Bayesian Model for Concept Drift?
How to Update Bayesian Model for Concept Drift? 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 - SnowflakeMediumData ScientistContrast FCF vs NI; choose one statement
This question evaluates financial statement analysis skills—specifically reconciling net income to free cash flow, identifying accounting and working-capital red flags, and selecting which single statement best informs credit risk, profitability trends, and cash runway, thereby testing valuation, solvency, and financial-modeling competency in the Statistics & Math domain. It is commonly asked because interviewers probe both conceptual understanding and practical application of accrual versus cash accounting, the effects of non‑cash charges, capex and working‑capital movements on valuation, and awareness of which metrics (for example FCF margin, interest coverage, and current ratio) become unreliable or unobtainable when only one statement is available.
Statistics & MathTechnical Screen - SpokeoMediumData ScientistAnswer 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 - SquarepointMediumData ScientistCompare 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 ScientistCompare 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 ScientistEstimate 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 ScientistExplain 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 ScientistFind 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 - StripeMediumData ScientistChoose 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 ScientistCompute 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 - ThumbtackMediumData ScientistTest regional response-rate differences rigorously
This question evaluates applied statistical modeling and causal-inference competencies, including adjustment for confounding, analysis of proportion/count outcomes, variance estimation under clustering, multiple-comparison control, diagnostic detection of Simpson’s paradox, and clear effect-size reporting; it is categorized under Statistics & Math and emphasizes practical application with necessary conceptual understanding. Such problems are commonly asked to assess the ability to justify and interpret comparative analyses that account for covariate mix, temporal structure, and multiple-testing concerns, and this summary is in English.
Statistics & MathOnsite - TikTokHardData ScientistAct when A/B result is not significant
This question evaluates a candidate's competency in experimental design and statistical decision-making, covering sample size calculation, variance-reduction methods, interpretation of non-significant A/B results, multiplicity control, and sequential/Bayesian decision frameworks.
Statistics & MathOnsite - TikTokEasyData ScientistCalculate Expected Draws for X > 0.8 in Uniform(0,1)
This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Calculate Expected Draws for X > 0.8 in Uniform(0,1) states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathTechnical Screen - TikTokMediumData ScientistCompute cluster-aware significance and sequential corrections
This question evaluates competency in clustered randomized experiment analysis, including calculation of design effect and effective sample size, cluster-robust inference for differences in proportions, sequential alpha spending (O’Brien–Fleming-style) and comparisons with Bonferroni, Holm–Bonferroni adjustments for multiple guardrail metrics, and Bayesian ROPE interpretation. It is in the Statistics & Math domain and is commonly asked to probe how candidates handle intra-cluster correlation, control Type I error across interim looks and multiple metrics, and demonstrate both conceptual understanding and practical application of power, duration, and multiplicity trade-offs.
Statistics & MathHR Screen - TikTokHardData ScientistControl confounding in observational ad lift
This question evaluates mastery of observational causal inference for ATE estimation, covering causal DAGs and identification, pre-treatment adjustment, propensity-score and inverse-probability/doubly-robust estimation, diagnostic checks, sensitivity analysis for unobserved confounding, and variance/uncertainty quantification in the context of ad exposure data. It is commonly asked because real-world advertising analyses cannot rely on randomization and interviewers need assurance of both conceptual understanding of identification assumptions and practical application of estimation and diagnostic techniques; the category is Statistics & Math and the level of abstraction spans conceptual reasoning and applied implementation.
Statistics & MathOnsite - TikTokMediumData ScientistDerive L1 vs L2 effects with correlation
This question evaluates understanding of regularization methods (ridge/L2, LASSO/L1, and elastic net), multicollinearity effects, geometric intuition of constraint sets, and hyperparameter influence on coefficient patterns in the Statistics & Math domain.
Statistics & MathTechnical Screen - TikTokEasyData ScientistTest Billboard Campaign Conversion Rate Exceeds 60%
Evaluates one-sample proportion testing for a billboard conversion rate with 65 conversions out of 100 users. Strong answers state one-sided hypotheses, compute the standard error and confidence interval, run the correct z test against 60%, and interpret why statistical evidence may be insufficient.
Statistics & MathOnsite - TikTokHardData ScientistUse DiD for staggered treatment adoption
This question evaluates proficiency in causal inference for panel data, specifically difference-in-differences with staggered adoption, heterogeneous and dynamic treatment effects, event-study design, pre-trend diagnostics, cluster-robust inference, and comparison with propensity-score matching.
Statistics & MathTechnical Screen - Two SigmaEasyData ScientistAnswer four core statistics questions
This multipart problem evaluates competency in probability and mathematical statistics, covering order statistics and covariance, the rationale for degrees of freedom in sample variance, z-test sample size calculation, and a one-sided concentration inequality, categorized under Statistics & Math for a Data Scientist role and combining conceptual derivations with practical formula application. Such questions are commonly asked to verify mathematical rigor in deriving expectations and covariances, understanding sampling distributions and unbiased estimation, applying hypothesis testing power formulas, and proving probabilistic inequalities that underpin statistical reasoning.
Statistics & MathTechnical Screen - Two SigmaHardData ScientistExplain why the t-statistic helps
This question evaluates understanding of the t-statistic, standardized effect sizes, standard errors, hypothesis testing, and interpretation of statistical evidence within the Statistics & Math domain, and it targets conceptual understanding with practical application implications.
Statistics & MathTechnical Screen - Two SigmaHardData ScientistWhy Use a t-Statistic?
This problem tests your conceptual understanding of the t-statistic, specifically how sample parameters influence its value and how it bridges the gap between estimation and hypothesis testing.
Statistics & MathTechnical ScreenStatisticsHypothesis TestingQuantitative Finance - Two SigmaEasyData ScientistWhy is the t-statistic useful
This question tests the candidate's conceptual understanding of the t-statistic, specifically its role in hypothesis testing when population parameters are unknown.
Statistics & MathTechnical ScreenStatisticsHypothesis TestingInference - Two SigmaHardData ScientistWhy use the t-statistic?
This question tests the conceptual understanding of the t-statistic, specifically why it is used instead of the Z-statistic when population parameters are unknown and how it accounts for uncertainty in sample variance.
Statistics & MathTechnical ScreenStatisticsHypothesis TestingT-Distribution