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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 751–780 of 1971 results
- GoogleHardData ScientistDefine 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 ScientistDemonstrate 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 ScientistDemonstrate 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 ScientistDerive 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 ScientistDescribe 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 ScientistDescribe 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 ScientistDescribe 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 ScientistDesign 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 ScientistDesign 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 ScientistDesign 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 ScientistDesign 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 ScientistDesign 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 ScientistDesign 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 ScientistDesign 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 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 - GoogleEasyData ScientistDesign 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 ScientistDetermine 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 ScientistDetermine 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 ScientistDiagnose 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 ScientistDiagnose 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 ScientistDiagnose 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 ScientistDiagnose 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 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 ScientistEstimate 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 ScientistEstimate 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 ScientistEstimate 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 ScientistEstimate 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 ScientistEvaluate 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 ScientistEvaluate 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 ScientistEvaluate 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