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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 361–390 of 513 results

  • NetflixMediumData Scientist
    Estimate ATE of personalization on streaming

    This question evaluates causal inference and experimental-analysis competencies by asking for estimation of the average treatment effect (ATE) of personalization on minutes streamed, reporting a 95% confidence interval, and reasoning about the use of pre-treatment covariates, and it sits in the Analytics & Experimentation domain for a Data Scientist role. It is commonly asked to assess application of randomized experiment analysis and statistical inference while probing conceptual understanding of causal assumptions and covariate adjustment, testing both conceptual understanding and practical application.

    Analytics & ExperimentationOnsite
  • NetflixEasyData Scientist
    Estimate ATE, ITT, and TOT from experiment

    This question tests the ability to distinguish and calculate Average Treatment Effect (ATE), Intent-to-Treat (ITT), and Treatment-on-the-Treated (TOT) in the presence of non-compliance.

    Analytics & ExperimentationOnsiteCausal InferenceExperimentationInstrumental Variables
  • NetflixMediumData Scientist
    How to Design Effective A/B Tests for Onboarding

    Evaluates A/B test design for a redesigned onboarding flow in a subscription app. Strong answers define activation, user-level randomization, primary and guardrail metrics, sample size, sequential monitoring, and decisions when activation improves but support burden rises.

    Analytics & ExperimentationOnsite
  • NextdoorMediumData Scientist
    Measure Local News Launch Success

    This problem tests your ability to design an experimentation framework for a localized product launch and identify potential confounding factors and interference effects.

    Analytics & ExperimentationTechnical ScreenExperimentationCausal InferenceMetrics
  • OneMain FinancialMediumData Scientist
    Calculate Break-Even Point and Profit Impact Analysis

    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 Calculate Break-Even Point and Profit Impact Analysis states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Analytics & ExperimentationTechnical Screen
  • OneMain FinancialEasyData Scientist
    Calculate Break-even for New Credit Card Product Launch

    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 Calculate Break-even for New Credit Card Product Launch states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Analytics & ExperimentationTechnical Screen
  • OneMain FinancialMediumData Scientist
    Calculate Profit-Maximizing Price and Validate with Additional Data

    Evaluates profit-maximizing pricing from demand curves, marginal revenue, marginal cost, and validation data. Strong answers derive optimal price and quantity, provide examples, and request experiments or elasticity evidence.

    Analytics & ExperimentationOnsite
  • OneMain FinancialMediumData Scientist
    Determine Channel Performance with Additional Metrics Needed

    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 Determine Channel Performance with Additional Metrics Needed states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Analytics & ExperimentationTechnical Screen
  • OneMain FinancialMediumData Scientist
    Determine Optimal Marketing Budget Allocation for Maximum Profit

    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 Determine Optimal Marketing Budget Allocation for Maximum Profit states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Analytics & ExperimentationOnline Assessment
  • OneMain FinancialEasyData Scientist
    Evaluate shift from branch to digital channel

    This question evaluates a data scientist's ability to analyze channel unit economics, design growth experiments and metrics, and assess operational, fraud, and credit risk implications for shifting acquisition from branch to digital in a credit-card business.

    Analytics & ExperimentationTechnical Screen
  • OneMain FinancialMediumData Scientist
    Maximize credit card portfolio profit

    This problem tests your ability to model expected profitability by balancing credit risk (probability of default) against revenue generation and defining optimal decision thresholds.

    Analytics & ExperimentationTechnical ScreenCredit RiskProfit ModelingDecision Strategy
  • OneMain FinancialMediumData Scientist
    Optimize SaaS pricing and profit

    This question evaluates pricing optimization, linear demand modeling, capacity-constrained profit maximization, and the impact of subscription churn on lifetime value within an Analytics & Experimentation data-science context.

    Analytics & ExperimentationTechnical Screen
  • OpenAIMediumData Scientist
    Analyze A/B Test Results for Subscription Conversion Rates

    Evaluates A/B test analysis for a limited-time free trial offer. Strong answers compute paid-conversion lift, account for trial starts and churn, test statistical significance, and make a launch decision using retained paid value, revenue, guardrails, and long-term holdouts.

    Analytics & ExperimentationOnline Assessment
  • OpenAIHardData Scientist
    Assess free-month promotion impact

    This question tests your ability to design a rigorous experimentation framework to measure the causal impact of a promotional offer while accounting for self-selection bias and long-term churn behavior.

    Analytics & ExperimentationTechnical ScreenA/B TestingCausal InferenceProduct Analytics
  • OpenAIHardData Scientist
    Design a free-month experiment

    This question evaluates experimental design, causal inference, metric selection, bias mitigation, ROI estimation, and stakeholder communication skills within the Analytics & Experimentation domain for a Data Scientist role.

    Analytics & ExperimentationTechnical Screen
  • OpenAIHardData Scientist
    Design and Defend a Free-Trial Conversion Analysis

    Walk through how to plan, execute, and defend a free-trial conversion analysis end to end: cohort definition, data-quality checks, standards for a credible insight, and a recommendation deck that survives live pushback.

    Analytics & ExperimentationOnsiteexperimentationmetricscase-study
  • OpenAIMediumData Scientist
    Determine Metrics to Measure Free-Trial Impact on Subscriptions

    Determine Metrics to Measure Free-Trial Impact on Subscriptions evaluates metric design, causal reasoning, experiment setup, diagnostics, SQL/statistical checks, and recommendations in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Analytics & ExperimentationOnline Assessment
  • OpenAIEasyData Scientist
    Evaluate a free-trial A/B test

    This question tests your ability to design an A/B test for a freemium product, interpret statistical results, and address potential biases like cannibalization or selection effects.

    Analytics & ExperimentationTechnical ScreenA/B TestingMetricsRetention
  • OpenAIMediumData Scientist
    How would you evaluate a free-trial A/B test?

    Evaluates skills in A/B test design and causal inference within the Analytics & Experimentation domain, emphasizing precise metric definition (including guardrails), choice of analysis population (ITT vs per‑protocol), handling of post‑treatment selection, and interpretation of binary conversion and retention metrics; the abstraction level is technical and oriented toward intermediate-to-senior data scientists who must combine statistical rigor with product impact thinking. Commonly asked because it tests the ability to balance acquisition versus downstream retention and revenue, to identify typical analysis pitfalls (time-window errors, incorrect joins/denominators, leakage, peeking, and selection bias), and to translate experiment results into a business recommendation linked to value metrics like LTV and payback period.

    Analytics & ExperimentationTechnical Screen
  • OpenAIHardData Scientist
    Measure free-month promotion impact

    This question tests the ability to design an experiment for a subscription product, focusing on causal inference, handling right-censoring in cohort data, and calculating the Return on Investment (ROI) for a promotional offer.

    Analytics & ExperimentationTechnical ScreenCausal InferenceExperiment DesignROI
  • OtherHardData Scientist
    Decide launch with asymmetric costs

    This question evaluates a data scientist's ability to integrate statistical inference (p‑values, Type I/II errors, and prior probabilities) with decision analysis and financial impact assessment (NPV, rollout and rollback costs) in the context of A/B testing.

    Analytics & ExperimentationTechnical Screen
  • OtherHardData Scientist
    Define goals and success metrics for subscriber-only features

    This question evaluates a data scientist's competency in product analytics and experimentation, specifically goal selection, success metric definition, ROI calculation, cannibalization analysis, and end-to-end experiment and instrumentation design for subscriber-only features.

    Analytics & ExperimentationTechnical Screen
  • OtherHardData Scientist
    Design an A/B test with guardrails

    This question evaluates a data scientist's skills in experimental design, hypothesis testing, statistical power and sample-size calculation, randomization and contamination control, pre-registration planning, and multiplicity adjustment for A/B testing.

    Analytics & ExperimentationOnsite
  • OtherHardData Scientist
    Design metrics and experiment

    This question evaluates a candidate's competency in experimental design, success-metric definition, event instrumentation, causal inference for heterogeneous treatment effects, and statistical power and sample-size calculations for subscription-product analytics.

    Analytics & ExperimentationTechnical Screen
  • OtherMediumData Scientist
    Design metrics resilient to data quality

    This question evaluates the ability to design robust data-quality metrics and apply SQL window-function techniques for deduplication and time-windowed completeness calculations, focusing on quantifying how ingestion delays, duplicates, and negative amounts can bias payment metrics.

    Analytics & ExperimentationTechnical Screen
  • OtherEasyData Scientist
    How would you measure and experiment on harmful content?

    This question evaluates a data scientist's competency in measuring and experimenting on harmful user-generated content, focusing on severity quantification, metric selection, and randomized experiment design within the analytics and experimentation domain.

    Analytics & ExperimentationTechnical Screen
  • OtherMediumData Scientist
    Separate demand from supply for jeans

    This question evaluates a data scientist's ability to perform data-driven diagnostics, funnel-metric construction, quantitative decision-rule design, and experimentation planning to distinguish demand-side from supply-side constraints in a marketplace jeans category.

    Analytics & ExperimentationOnsite
  • PayPalMediumData Scientist
    Analyze Transactions for Risk and Implement Mitigation Strategies

    Analyze Transactions for Risk and Implement Mitigation Strategies evaluates metric design, causal reasoning, experiment setup, diagnostics, SQL/statistical checks, and recommendations in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Analytics & ExperimentationOnsite
  • PayPalHardData Scientist
    Assess card transactions and plan risk strategy

    Assess card transactions and plan risk strategy evaluates metric design, causal reasoning, experiment setup, diagnostics, SQL/statistical checks, and recommendations in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Analytics & ExperimentationOnsite
  • PayPalMediumData Scientist
    Boost User Login Rate: Key Metrics to Monitor

    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 Boost User Login Rate: Key Metrics to Monitor states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Analytics & ExperimentationOnsite