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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 91–120 of 1076 results

  • AmazonMediumData Scientist
    Mitigate 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 Scientist
    Optimize 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 Scientist
    Plan 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 Scientist
    Prioritize 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 Scientist
    Profile 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 Scientist
    Resolve 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 Scientist
    Resolve 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 Scientist
    Respond to Difficult Critical Feedback

    Practice discussing difficult feedback with a concrete example, an observable behavior change, and evidence of improvement.

    Behavioral & LeadershipTechnical Screen
  • AmazonMediumData Scientist
    Select 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 Scientist
    Solve 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 Scientist
    Solve 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 Scientist
    Solve 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 Scientist
    Solve 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 Scientist
    Understand 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 Scientist
    Verify 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 Scientist
    Walk 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 Scientist
    Compare 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 Scientist
    Compare 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 Scientist
    Construct 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 Scientist
    Describe 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 Scientist
    Design 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 Scientist
    Design 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 Scientist
    Diagnose 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 Scientist
    Examine 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 Scientist
    Find 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 Scientist
    How 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 Scientist
    Demonstrate 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 Scientist
    Find 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 Scientist
    Implement 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 Scientist
    Train 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