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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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- 546
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- 11
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- 8
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Showing 91–120 of 1076 results
- AmazonMediumData ScientistMitigate Data Mistakes and Improve Team Efficiency
This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Mitigate Data Mistakes and Improve Team Efficiency states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipTechnical Screen - AmazonMediumData ScientistOptimize Predictive Analytics: Feature Engineering to Model Evaluation
Evaluates end-to-end predictive analytics project communication for a technical data-science interview. Strong answers cover business objectives, data, leakage controls, features, models, evaluation, errors, and impact.
Machine LearningTechnical Screen - AmazonHardData ScientistPlan and analyze an A/B test
This question tests the ability to design a statistically rigorous A/B test by accounting for clustered randomization, sequential testing boundaries, and multiple comparison corrections.
Statistics & MathTechnical ScreenExperimental DesignPower AnalysisClustered Data - AmazonHardData ScientistPrioritize a new warehouse proposal with data
This question evaluates demand forecasting, network optimization, five-year NPV financial modeling, experiment and quasi-experiment design for incrementality estimation, sensitivity analysis, and stakeholder communication within the analytics & experimentation domain for data science roles focused on warehouse/fulfillment center decisions.
Analytics & ExperimentationTechnical Screen - AmazonMediumData ScientistProfile and visualize an unfamiliar dataset
This question evaluates a data scientist's competency in exploratory data analysis, data quality assessment, time-series aggregation, visualization design, and concise stakeholder communication when working with an undocumented events-plus-purchases CSV.
Analytics & ExperimentationTechnical Screen - AmazonMediumData ScientistResolve Team Conflicts and Deliver Beyond Project Scope
This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Resolve Team Conflicts and Deliver Beyond Project Scope states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipTechnical Screen - AmazonMediumData ScientistResolve a team conflict decisively
The question evaluates conflict-resolution, decisive leadership, stakeholder management, evidence-based decision-making, communication under time pressure, and the ability to enforce delivery timelines and run post-mortems within a Data Scientist role.
Behavioral & LeadershipTechnical Screen - AmazonMediumData ScientistRespond to Difficult Critical Feedback
Practice discussing difficult feedback with a concrete example, an observable behavior change, and evidence of improvement.
Behavioral & LeadershipTechnical Screen - AmazonMediumData ScientistSelect Top Customers Using Transaction Data Filters
This question evaluates a candidate's ability to perform data aggregation, filtering, ranking, and deterministic tie-breaking on transactional datasets, assessing skills in Data Manipulation (SQL/Python).
Data Manipulation (SQL/Python)Technical Screen - AmazonMediumData ScientistSolve Algorithmic Challenges in Online Coding Assessments
This question evaluates proficiency in fundamental algorithmic problem-solving, specifically array manipulation, string processing, and the use of basic data structures along with performance and complexity reasoning.
Coding & AlgorithmsTechnical Screen - AmazonMediumData ScientistSolve Search Insert Position Using Binary Search
This question evaluates proficiency in binary search, algorithmic implementation on sorted arrays, and understanding of time complexity and index management.
Coding & AlgorithmsTechnical Screen - AmazonMediumData ScientistSolve stock, BFS path, and merge intervals
This question evaluates algorithmic problem solving across array scanning, BFS-based constrained shortest-path selection, and interval merging, with emphasis on time/space complexity reasoning, correctness proofs, and thorough edge-case handling. It is commonly asked to assess efficiency guarantees (e.g.
Coding & AlgorithmsTechnical Screen - AmazonEasyData ScientistSolve two string DP/hash problems
This question set evaluates string-processing and algorithmic problem-solving skills, including encoding and transformation for unique representations and dynamic programming, memoization, and backtracking for enumerating all valid segmentations.
Coding & AlgorithmsTechnical Screen - AmazonMediumData ScientistUnderstand SQL: DELETE vs TRUNCATE, VIEW vs TABLE, CROSS JOIN
This question evaluates a candidate's understanding of core SQL concepts and data-manipulation competencies, covering the behavior of data-deletion operations, distinctions between logical and physical data structures, and join semantics.
Data Manipulation (SQL/Python)Technical Screen - AmazonMediumData ScientistVerify subscriptions and analyze orders with SQL/Python
This question evaluates proficiency in SQL and pandas data manipulation, covering data-quality validation, temporal sequence reasoning, deduplication, deterministic aggregation, and tie-breaking logic.
Data Manipulation (SQL/Python)Technical Screen - AmazonEasyData ScientistWalk through an A/B test end-to-end
This question evaluates a data scientist's competencies in experimental design, statistical inference, causal reasoning, metric selection, and data quality assurance for A/B testing.
Analytics & ExperimentationTechnical Screen - AppleMediumData ScientistCompare Normal and Poisson Distributions in Statistics
Evaluates statistical understanding of Normal and Poisson distributions for counts and continuous measurements. Strong answers compare support, parameters, use cases, Normal approximation conditions, and mean-variance derivations.
Statistics & MathTechnical Screen - AppleMediumData ScientistCompare Normal vs Poisson; test dispersion and approximate tails
This question evaluates a data scientist's competency in statistical inference for count data, covering MLE and asymptotic variance estimation, Wald confidence intervals, tests for equidispersion versus overdispersion, Normal approximation with continuity correction for Poisson tails, and model selection diagnostics.
Statistics & MathTechnical Screen - AppleMediumData ScientistConstruct a Churn-Prediction Pipeline Using Scikit-Learn
This question tests practical machine learning engineering skills, specifically the ability to construct an end-to-end classification pipeline for imbalanced tabular data. It evaluates knowledge of preprocessing, model validation, probability calibration, and production packaging — core competencies assessed in data scientist interviews.
Machine LearningTechnical Screen - AppleMediumData ScientistDescribe Your Role in a Recent Successful Project
This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Describe Your Role in a Recent Successful Project states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipTechnical Screen - AppleMediumData ScientistDesign A/B Test for Search Feature Effectiveness
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 Design A/B Test for Search Feature Effectiveness states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Analytics & ExperimentationTechnical Screen - AppleMediumData ScientistDesign Siri-vs-GPT query routing
This question evaluates a data scientist's competency in designing an end-to-end query-routing system between an on-device personal assistant and a large language model assistant, encompassing objectives, success metrics, ground-truth labeling, feature and model choices, ambiguity and multi-turn handling, and evaluation strategies.
Machine LearningTechnical Screen - AppleMediumData ScientistDiagnose post-release conversion regression rigorously
This question tests the ability to diagnose a post-release metric regression in the absence of a control group by utilizing quasi-experimental design and causal inference methods.
Analytics & ExperimentationTechnical ScreenCausal InferenceRoot Cause AnalysisExperimentation - AppleMediumData ScientistExamine Data to Boost Instagram Purchases Effectively
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 Examine Data to Boost Instagram Purchases Effectively states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Analytics & ExperimentationTechnical Screen - AppleMediumData ScientistFind Maximum Sum of Contiguous Subarray Length k
This question evaluates skill in array manipulation and computing aggregate metrics over fixed-length intervals, along with understanding of algorithmic complexity and trade-offs between runtime and memory.
Coding & AlgorithmsTechnical Screen - AppleEasyData ScientistHow would you critique this regression?
An Apple Data Scientist technical-screen statistics question that asks you to critique another analyst's linear-regression workflow for modeling website dwell time. It tests OLS assumptions (and why marginal normality of Y is not one of them), model-selection and overfitting bias from exhaustive interaction search, diagnostics and validation, and the distinction between prediction, inference, and causal goals on skewed outcome data.
Statistics & MathTechnical Screen - AtlassianMediumData ScientistDemonstrate motivation, feedback, and prioritization
This question evaluates motivation, constructive feedback, competing-priority prioritization, customer-focused problem solving, and team leadership competencies within a Data Scientist role.
Behavioral & LeadershipTechnical Screen - AtlassianMediumData ScientistFind 2023 NCAA championship winner
This question evaluates proficiency in SQL data manipulation and relational reasoning, testing the ability to identify a championship winner from game result records across related tables in the Data Manipulation (SQL/Python) domain for data scientist roles.
Data Manipulation (SQL/Python)Technical Screen - AtlassianMediumData ScientistImplement Real-Time Rate Limiting for Web Service Requests
This question evaluates understanding of real-time rate limiting, time-windowed traffic control, and efficient per-client state management under algorithmic constraints.
Coding & AlgorithmsTechnical Screen - AtlassianMediumData ScientistTrain and evaluate logistic model with regularization
This question evaluates proficiency in supervised binary classification with logistic regression, implementation of L1 and L2 regularization, data preprocessing (missingness checks and standardization), hyperparameter selection via cross-validation, and model evaluation using ROC AUC and threshold-dependent metrics.
Machine LearningTechnical Screen