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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 751–780 of 1971 results

  • GoogleHardData Scientist
    Define and apply Gmail user segments

    A Google data scientist analytics screen: propose actionable Gmail user segments from behavioral metadata, validate their stability and separability over eight weeks, design targeted interventions with metrics and guardrails, and run a privacy-aware experiment to measure per-segment lift. Covers segmentation axes, validation metrics, k-anonymity and differential privacy, CUPED, and RICE roadmap prioritization.

    Analytics & ExperimentationTechnical Screen
  • GoogleMediumData Scientist
    Demonstrate leadership in data ambiguity

    This question evaluates leadership in data ambiguity, assessing competencies in diagnosing underperforming metrics or models, articulating quantified trade-offs, influencing cross-functional stakeholders with data and experiments, and designing operational safeguards and accountability mechanisms.

    Behavioral & LeadershipOnsite
  • GoogleMediumData Scientist
    Demonstrate stakeholder communication and influence

    This question evaluates a candidate's stakeholder communication and influence using data, specifically assessing the ability to present analysis to non-technical partners, manage pushback, make trade-offs, and demonstrate measurable outcomes in a cross-functional decision context for a Data Scientist role.

    Behavioral & LeadershipTechnical Screen
  • GoogleMediumData Scientist
    Derive MLEs and conditional Normal distributions

    This question evaluates proficiency in parametric inference and probability theory, specifically maximum likelihood estimation, bias of estimators, and conditioning in univariate and bivariate Normal distributions including constrained estimation of parameters.

    Statistics & MathTechnical Screen
  • GoogleMediumData Scientist
    Describe Overcoming Challenges and Persuading Non-Data Colleagues

    Evaluates behavioral interview storytelling for persuading non-data colleagues and resolving workplace challenges. Strong answers use STAR, translate analysis into business terms, handle objections, show collaboration, quantify outcomes, and reflect on lessons learned.

    Behavioral & LeadershipTechnical Screen
  • GoogleMediumData Scientist
    Describe Your Research and Cross-Functional Collaboration Experience

    Evaluates behavioral storytelling for research rigor and cross-functional collaboration in data science. Strong answers explain problem framing, methodology, validation, stakeholder alignment, impact, and limitations.

    Behavioral & LeadershipTechnical Screen
  • GoogleEasyData Scientist
    Describe a challenging project and how you succeeded

    This question evaluates a data scientist's ownership, technical depth in research and modeling, decision-making under constraints, stakeholder management, measurable impact orientation, and reflective learning, and it is categorized under Behavioral & Leadership for Data Scientist roles.

    Behavioral & LeadershipHR Screen
  • GoogleMediumData Scientist
    Design A/B Test for Google Maps UI Change

    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 Google Maps UI Change states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Analytics & ExperimentationOnsite
  • GoogleMediumData Scientist
    Design A/B Test for Subscription Price Increase Effectiveness

    Evaluates experiment design for SaaS subscription pricing and a multivariate sign-up CTA test. Strong answers address pricing-test risks, LTV metrics, factorial design, interaction effects, and guardrails.

    Analytics & ExperimentationOnsite
  • GoogleMediumData Scientist
    Design A/B Test to Isolate Product Usage Drop Causes

    Evaluates experimentation strategy for diagnosing a simultaneous product usage drop in the U.S. and Mexico. Strong answers identify confounders, design tests or quasi-experiments, control variables, and report causal lift.

    Analytics & ExperimentationTechnical Screen
  • GoogleMediumData Scientist
    Design Scalable Database and Analyze E-commerce Data

    This question evaluates relational database design and data-manipulation competencies, including schema modeling and normalization, SQL-based association analysis for co-purchases, and vectorized data transformation using Python/Pandas.

    Data Manipulation (SQL/Python)Technical Screen
  • GoogleMediumData Scientist
    Design a scalable video platform database

    This question evaluates relational database design and data engineering competencies—including schema modeling, many-to-many relationships, idempotent ingest, indexing and partitioning, OLTP versus analytics integration, GDPR-compliant deletion strategies, and query formulation—within the Data Manipulation (SQL/Python) domain for a Data Scientist role. It is commonly asked to assess both conceptual understanding and practical application of scalable data architectures, performance tuning, and compliance trade-offs, focusing on the ability to reason about schema choices, read/write optimization, and analytics integration without implementation details.

    Data Manipulation (SQL/Python)Technical Screen
  • GoogleEasyData Scientist
    Design an A/B test for search ranking

    This question tests the ability to design a statistically sound A/B test for a search ranking algorithm, focusing on metric selection, hypothesis formulation, and common pitfalls in experimentation.

    Analytics & ExperimentationHR ScreenA/B TestingMetricsHypothesis Testing
  • GoogleHardData Scientist
    Design an Unbiased Upgrade Experiment

    This question tests the ability to design an A/B test for a software upgrade, specifically focusing on handling non-compliance, selection bias, and the identification of causal effects in a real-world product environment.

    Analytics & ExperimentationTechnical ScreenCausal InferenceExperiment DesignA/B Testing
  • GoogleHardData Scientist
    Design 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
  • GoogleEasyData Scientist
    Design tests to measure latency impact

    A Google Data Scientist onsite case on measuring the causal impact of reduced YouTube video-start latency on engagement. It spans A/B design (primary metric, diagnostics, error/buffering guardrails), randomization unit and interference, power/MDE for heavy-tailed watch time, variance reduction (CUPED, stratification), analysis of conflicting movements, ratio-metric decomposition with Simpson’s paradox, and propensity score matching when randomization isn’t possible.

    Analytics & ExperimentationOnsite
  • GoogleMediumData Scientist
    Determine Impact of New Chat-Notification on User Engagement

    Determine Impact of New Chat-Notification on User Engagement 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 & MathTechnical Screen
  • GoogleEasyData Scientist
    Determine Normality of Single Observation with Z-Test

    Evaluates hypothesis testing for a single observation against a fully specified standard normal distribution. Strong answers state hypotheses, use z = x, define critical values and p-values, and note limitations.

    Statistics & MathTechnical Screen
  • GoogleHardData Scientist
    Diagnose Google Meet Disconnections and Assess Business Impact

    Evaluates reliability analytics for Google Meet disconnections and enterprise renewal impact. Strong answers define call drops, use client and server logs to localize root causes, estimate account-level retention impact, and prioritize fixes using quantified business risk.

    Analytics & ExperimentationTechnical Screen
  • GoogleMediumData Scientist
    Diagnose a metric drop in search time

    This question evaluates a data scientist's competency in precise metric and population definition, time‑to‑event and survival/hazard modeling, time‑series decomposition and change‑point analysis, instrumentation and traffic forensics, and experimental design for root‑cause identification.

    Analytics & ExperimentationOnsite
  • GoogleHardData Scientist
    Diagnose and fix flawed model fit

    This question tests your ability to diagnose poor model performance in a binary classification task involving imbalanced data, high-cardinality categorical features, and potential bias.

    Machine LearningTechnical ScreenClassificationImbalanced DataFeature Engineering
  • GoogleHardData Scientist
    Diagnose and reverse an adoption-rate decline

    This question evaluates a data scientist's competency in product analytics and experimentation, covering precise metric definition and validation, instrumentation and event quality checks, rapid triage of adoption regressions, hypothesis generation, experiment design, and causal inference.

    Analytics & ExperimentationOnsite
  • GoogleHardData Scientist
    Estimate 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 Scientist
    Estimate percentile from buckets

    Estimate a percentile from histogram buckets by locating the cumulative-count bucket, explaining why midpoint can be poor, interpolating within the bucket under explicit assumptions, handling log-spaced buckets and edge cases, and reporting uncertainty when buckets are coarse.

    Statistics & MathTechnical Screen
  • GoogleMediumData Scientist
    Estimate population singletons from a 10% log

    This question evaluates mastery of statistical estimation and sampling theory, including recognition of bias from subsampling, frequency‑of‑frequencies modeling for rare events, uncertainty quantification under heavy‑tailed counts, and design of simulation studies.

    Statistics & MathTechnical Screen
  • GoogleMediumData Scientist
    Estimate unbiased ad scores with many reviewers

    This problem tests the ability to design an estimation framework that accounts for rater bias and variance, specifically applying concepts like hierarchical modeling or fixed-effect normalization to estimate latent variables.

    Statistics & MathTechnical ScreenStatisticsModelingBias
  • GoogleEasyData Scientist
    Estimate weather’s effect on mental health

    This problem tests the ability to design an observational study to measure the causal impact of meteorological variables on self-reported mental health scores, focusing on confounding variables and identification strategies.

    Statistics & MathHR ScreenCausal InferenceRegressionConfounding
  • GoogleHardData Scientist
    Evaluate AI Workflow Product Metrics

    Design an end-to-end measurement and experimentation framework for a generative AI workflow-suggestion tool. Tests metric taxonomy, funnel analytics, instrumentation pitfalls, and causal inference under interference.

    Analytics & ExperimentationTechnical Screenexperimentationproduct-metricscausal-inference
  • GoogleMediumData Scientist
    Evaluate Auto-Reply Feature Success with Metrics and Experiments

    Evaluates metrics and experimentation for an auto-reply suggestion feature in chat. Strong answers define adoption, latency, conversation quality, retention, and safety guardrails, design a causal experiment, and diagnose inconclusive results through funnel, segment, quality, and UI analyses.

    Analytics & ExperimentationTechnical Screen
  • GoogleMediumData Scientist
    Evaluate Optimal Jogging Routes Feature with A/B Testing

    Evaluates A/B test design for Google Maps jogging route recommendations. Strong answers define jogging intent and exposure, measure completed runs and satisfaction, include safety and privacy guardrails, and specify randomization, MDE, power, logging, and rollout criteria.

    Analytics & ExperimentationTechnical Screen