Data Scientist Interview Questions

Showing 1951–1971 of 1971 results

• WorldquantMedium·Data Scientist
  Find the Expected Number of Record Maxima

  A permutation of the distinct values `1` through `100` is revealed from left to right. Explain the assumptions and derivation clearly, check edge cases, and show how the result changes when those assumptions no longer hold.

  Statistics & MathTechnical Screen
• WorldquantMedium·Data Scientist
  Price a Sequential Four-Box Search Game

  Four boxes contain one \$100 prize. Explain the assumptions and derivation clearly, check edge cases, and show how the result changes when those assumptions no longer hold.

  Statistics & MathTechnical Screen
• YahooEasy·Data Scientist
  Calculate Expected Flips for Heads-Tails Sequence

  This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Calculate Expected Flips for Heads-Tails Sequence states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

  Statistics & MathTechnical Screen
• YahooMedium·Data Scientist
  Calculate Total Spend and Identify Key User Metrics

  This question evaluates a data scientist's proficiency in transactional data manipulation using SQL and Python, focusing on aggregation, ranking, joins, date arithmetic, and numeric rounding to produce user-level and time-series metrics.

  Data Manipulation (SQL/Python)Technical Screen
• YahooMedium·Data Scientist
  Evaluate Widget Impact on User Engagement with A/B Testing

  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 Evaluate Widget Impact on User Engagement with A/B Testing states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

  Analytics & ExperimentationTechnical Screen
• YahooMedium·Data Scientist
  Merge words by head-tail chaining

  This question evaluates graph-theoretic reasoning and string-manipulation skills, focusing on the ability to reason about ordering constraints, edge cases like self-loops and multiple identical relationships, and traversal over relationships between items.

  Coding & AlgorithmsTechnical Screen
• YahooMedium·Data Scientist
  Prove Equal Probability Impossible with Relabeled Dice Faces

  This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Prove Equal Probability Impossible with Relabeled Dice Faces states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

  Statistics & MathTechnical Screen
• YahooMedium·Data Scientist
  Solve Data Structure Challenges with Python Algorithms

  This question evaluates proficiency in fundamental data structure manipulation and string-processing algorithms, specifically preserving insertion order during list deduplication and performing iterative overlap-based word merging.

  Coding & AlgorithmsTechnical Screen
• YYelpHard·Data Scientist
  Design a Cold-Start-Aware Recommender

  This question evaluates a data scientist's expertise in production recommender systems, covering cold-start strategies, two-stage retrieval and ranking model design, multimodal feature engineering, exploration–exploitation, bias-corrected experimentation, and low-latency serving.

  Machine LearningOnsite
• YYelpEasy·Data Scientist
  Estimate Experiment Duration with Power Analysis

  This question tests the ability to perform a power analysis to calculate sample size requirements for an A/B test and derive the experiment duration based on traffic constraints.

  Analytics & ExperimentationTechnical ScreenA/B TestingPower AnalysisStatistics
• YYelpHard·Data Scientist
  Handle PM Ambiguity and Drive Outcomes

  This question evaluates leadership, stakeholder management, and incident response competencies within a data science context, including the ability to define measurable success metrics, negotiate scope under ambiguity, and make data-driven decisions during product regressions.

  Behavioral & LeadershipOnsite
• YYelpEasy·Data Scientist
  Recommend a Decision After a Nonsignificant Experiment

  This question tests the ability to interpret nonsignificant experimental results and formulate data-driven business recommendations beyond simple hypothesis testing.

  Analytics & ExperimentationTechnical ScreenA/B TestingHypothesis TestingProduct Analytics
• YYelpEasy·Data Scientist
  Return Integers in Descending Ranked Order

  This problem tests the ability to manipulate lists and sort data while maintaining the relative order of duplicate elements using common programming patterns.

  Coding & AlgorithmsTechnical ScreenSortingArraysAlgorithms
• ZAZest AIHard·Data Scientist
  Build a fair loan classifier

  This question evaluates competency in supervised classification and credit risk modeling, covering data exploration and preparation, model selection, evaluation metrics, threshold setting, fairness and regulatory considerations, interpretability, validation, and monitoring.

  Machine LearningOnsite
• ZAZest AIHard·Data Scientist
  Compute tree depth and meeting rooms

  This question evaluates skills in tree traversal and recursion for computing maximum depth of a binary tree, alongside interval scheduling and resource allocation for determining the minimum number of meeting rooms, testing reasoning about data structures such as trees and interval endpoints.

  Coding & AlgorithmsOnsite
• ZAZest AIHard·Data Scientist
  Diagnose overfitting from error curves

  This question evaluates the ability to recognize and diagnose model generalization problems—specifically overfitting—by interpreting training, validation, and test error curves and understanding validation procedures and sources of variance.

  Machine LearningOnsite
• ZooxEasy·Data Scientist
  Choose fastest way to transfer 2 TB

  This question evaluates a candidate's ability to compare large-scale data transfer methods and reason about trade-offs among bandwidth, latency, security, cost, and logistics, reflecting competency in data engineering, networking, and systems design.

  Coding & AlgorithmsOnsite
• ZooxMedium·Data Scientist
  Compute posterior for biased coin after 3H1T

  This question evaluates a candidate's understanding of Bayesian inference, computation of posteriors and Bayes factors, posterior predictive probabilities, and decision-theoretic model selection in a simple biased-coin scenario.

  Statistics & MathTechnical Screen
• ZooxMedium·Data Scientist
  Describe resolving a high-stakes research disagreement

  This question evaluates a data scientist's competency in stakeholder communication, leadership in research contexts, and technical reasoning about research design and probability/statistics assumptions, and is categorized under Behavioral & Leadership.

  Behavioral & LeadershipTechnical Screen
• ZooxMedium·Data Scientist
  Design navigation-safety simulation parameters and experiments

  This problem tests your ability to design a high-reliability simulation framework using variance reduction techniques and statistical validation methods to evaluate rare-event autonomous driving scenarios.

  Machine LearningTechnical ScreenSimulationRare-Event-EstimationImportance-Sampling
• ZooxEasy·Data Scientist
  Solve estimation and probability brainteasers

  This question evaluates quantitative estimation, unit conversion, geometric scaling, and basic probability skills across multiple short brainteaser prompts.

  Statistics & MathOnsite