Katkat

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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 241–263 of 263 results

  • TikTokMediumData Scientist
    Analyze promo anomaly and design risk guardrails

    This question evaluates a candidate's ability to diagnose promotional anomalies, distinguish coordinated abuse from organic virality, design real-time approve/hold/reject decisioning with cost trade-offs, and specify experiment and monitoring plans, testing competencies in fraud analytics, operational risk modeling, and experimentation.

    Analytics & ExperimentationHR Screen
  • TikTokMediumData Scientist
    Compute cluster-aware significance and sequential corrections

    This question evaluates competency in clustered randomized experiment analysis, including calculation of design effect and effective sample size, cluster-robust inference for differences in proportions, sequential alpha spending (O’Brien–Fleming-style) and comparisons with Bonferroni, Holm–Bonferroni adjustments for multiple guardrail metrics, and Bayesian ROPE interpretation. It is in the Statistics & Math domain and is commonly asked to probe how candidates handle intra-cluster correlation, control Type I error across interim looks and multiple metrics, and demonstrate both conceptual understanding and practical application of power, duration, and multiplicity trade-offs.

    Statistics & MathHR Screen
  • TikTokMediumData Scientist
    Demonstrate leadership in cross-functional disagreement

    This question evaluates leadership, cross-functional collaboration, stakeholder management, experimental design, and metric-driven decision-making competencies in a data scientist context, with emphasis on trade-off reasoning and end-to-end execution.

    Behavioral & LeadershipHR Screen
  • TikTokHardData Scientist
    Design an interference-robust A/B test for monetization

    This question evaluates experimental design and causal inference skills within Analytics & Experimentation, emphasizing interference mitigation, clustering and randomization choices, eligibility and exposure rules, metric hierarchy and guardrails, power and duration planning, variance-reduction techniques, and cluster-robust inference in a two-sided marketplace. It is commonly asked to test a data scientist's practical-application ability to balance monetization and growth trade-offs through precise statistical planning, pre-registered stopping rules, SRM detection, MDE and rollout decision thresholds rather than purely conceptual understanding.

    Analytics & ExperimentationHR Screen
  • TikTokHardData Scientist
    Design recommendations objective balancing growth and monetization

    This question evaluates a data scientist's competency in designing multi-objective recommender systems that balance user growth and creator monetization, covering ranking objective formulation, per-impression value estimation, constraint enforcement (latency, diversity, fairness/exposure), offline-to-online metric validation, cold-start and exploration strategies, and interference/attribution challenges within the Machine Learning domain. It is commonly asked to assess the ability to reason about trade-offs between business and user metrics, to define measurable objectives and validation plans, and to demonstrate both conceptual understanding and practical application of system design and evaluation.

    Machine LearningHR Screen
  • TikTokMediumData Scientist
    Explain Your Experience and Interest in Tech Role

    This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Explain Your Experience and Interest in Tech Role states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Behavioral & LeadershipHR Screen
  • TikTokMediumData Scientist
    Implement streaming SRM detector with late events

    This question evaluates proficiency in stateful stream processing, statistical anomaly detection for sample ratio mismatch, and scalable system design concerns such as deduplication, late/out-of-order event handling, real-time aggregation, chi-square testing with Yates correction, bot-rate mitigation, sharding, and replay validation.

    Coding & AlgorithmsHR Screen
  • TikTokMediumData Scientist
    Write SQL for 7-day geo-localized revenue dashboard

    This question evaluates SQL skills in time-zone aware local-date aggregation, idempotent event deduplication, cohorting for new versus returning users, calculation of revenue and conversion metrics, and anomaly detection via median-based drop flags.

    Data Manipulation (SQL/Python)HR Screen
  • UiPathMediumMachine Learning Engineer
    Reduce overfitting and explain the mean squared error loss

    A machine learning phone screen on how to diagnose and reduce overfitting, and on the mean squared error loss: its definition, what minimizing it estimates, its probabilistic interpretation, and when another loss works better. Tests fundamentals, mechanisms and trade-off reasoning.

    Machine LearningHR Screen
  • UpstartMediumSoftware Engineer
    Demonstrate Project Ownership

    Practice showing genuine end-to-end ownership through problem framing, trade-offs, delivery, recovery, and operational follow-through.

    Behavioral & LeadershipHR Screen
  • UpstartEasyData Scientist
    Derive logistic regression objective and gradients

    This question evaluates understanding of logistic regression, maximum likelihood estimation, cross-entropy (negative log-likelihood), L2 regularization, and the ability to compute model gradients for binary classification.

    Machine LearningHR Screen
  • UpstartMediumSoftware Engineer
    Describe Your Python Experience

    Present Python experience through maintained production work, correctness practices, operational judgment, and honest tool-selection limits.

    Software Engineering FundamentalsHR Screen
  • UpstartEasyData Scientist
    Determine distribution of aX+b when X~N(0,1)

    This problem tests your understanding of how linear (affine) transformations affect the properties of a normal distribution and the derivation of its mean and variance.

    Statistics & MathHR ScreenStatisticsProbabilityNormal Distribution
  • UpstartMediumSoftware Engineer
    Discuss Compensation Expectations

    Prepare a clear compensation-expectations response that asks for level and range context while considering the complete package.

    Behavioral & LeadershipHR Screen
  • UpstartHardData Scientist
    Formulate hypotheses and metrics for video-pin ramp

    This question evaluates experiment-design and data-science competencies including hypothesis specification, metric choice and guardrails, segmentation, interference handling, rollout planning, power/MDE considerations, and data-quality monitoring, and it falls under the Analytics & Experimentation domain.

    Analytics & ExperimentationHR Screen
  • UpstartEasyData Scientist
    Identify binomial model and compute moments

    This question tests the ability to identify a binomial process, express its probability mass function, and derive its fundamental moments (mean and variance).

    Statistics & MathHR ScreenStatisticsProbabilityBinomial Distribution
  • UpstartMediumSoftware Engineer
    Professional Introduction for a Recruiter Screen

    Prepare a focused recruiter-screen introduction that links concrete engineering ownership to the role you want next.

    Behavioral & LeadershipHR Screen
  • VisaMediumData Scientist
    Assess Cultural Fit and Motivation in Visa Interview

    This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Assess Cultural Fit and Motivation in Visa Interview states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Behavioral & LeadershipHR Screen
  • VoleonMediumData Scientist
    Describe Your Machine Learning Project Experience

    This interview question evaluates core ML concepts, assumptions, math intuition, training/evaluation trade-offs, and practical failure modes in a realistic interview setting. A strong answer for Describe Your Machine Learning Project Experience states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Machine LearningHR Screen
  • VoleonMediumData Scientist
    Discuss Résumé Highlights and Past Work Experience.

    This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Discuss Résumé Highlights and Past Work Experience. states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Behavioral & LeadershipHR Screen
  • WorkdayEasySoftware Engineer
    Explain What You Value in Your Next Engineering Role

    This question assesses your self-awareness, alignment with organizational culture, and your ability to articulate professional priorities through past experiences.

    Behavioral & LeadershipHR ScreenCareer GrowthCompany CultureSelf-Reflection
  • eBayMediumData Analyst
    Explain Joins and Write Coupon SQL

    This problem tests your ability to perform multi-table joins, handle temporal data, and apply conditional aggregation to compute business KPIs like conversion rates and total transaction value.

    Data Manipulation (SQL/Python)HR ScreenSQLJoinsAggregation
  • xAIMediumSoftware Engineer
    How Would You Prevent Hallucinations in an LLM-Based System?

    This question evaluates a candidate's understanding of hallucination in large language models, including underlying causes, detection, and system-level mitigation approaches, as well as their ability to reason about model reliability and failure modes.

    Machine LearningHR Screen