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Calculate Monthly Recurring Revenue (MRR) with SQL
This tests your ability to translate a business metric into a robust SQL query, handling time-series logic. A good answer filters for active subscriptions, sums the price, and correctly amortizes annual plans. A red flag is using incorrect date filtering.
What is a p-value, and what does 0.03 practically mean?
This tests your ability to translate stats into business decisions. A great answer defines p-value, compares 0.03 to the standard 0.05 threshold to reject the null hypothesis, and recommends shipping.
How do you handle timezones for a global daily sales report?
This tests your ability to translate ambiguous business needs (a "day") into a robust data model. First, clarify the business definition of a day. Then, store all event times in UTC and convert to the target timezone at query time for reporting.
Implement CDC from an OLTP database to a data warehouse
This tests your grasp of production system trade-offs. A good answer compares log-based and trigger-based CDC, focusing on source impact and data fidelity, then recommends log-based for its low overhead.
Propose a multi-touch attribution model and its data pipeline
This tests your ability to choose a practical data model under real-world constraints. Propose a time-decay or position-based model, then describe the data pipeline: event collection, identity resolution, and aggregation. A red flag is ignoring signal loss.
Transform a Time Series for a Gradient Boosting Model
Tests your ability to convert a sequential problem into a tabular one. A great answer covers creating lagged/rolling features and time-based features (e.g., day of week), and crucially, specifies a time-aware validation split.
How would you find leading indicators for long-term churn?
Tests your ability to connect a lagging business KPI to leading product metrics. A good answer defines churned/retained cohorts, analyzes first 30-day engagement differences (e.g., feature adoption), and validates findings. A red flag is jumping to ML models.
Calculate Daily Active Users (DAU) with SQL
This tests your ability to translate a business metric into a precise technical definition and query. A good answer defines "active," specifies the event data needed (user_id, timestamp, event_name), and uses COUNT(DISTINCT user_id).
Client-Side vs. Server-Side Event Tracking: Pros and Cons
Tests your grasp of data integrity trade-offs. A good answer defines both, contrasts reliability vs. implementation ease, and gives clear examples like 'payment_processed' (server) vs. 'button_click' (client). Red flag: Ignoring ad-blockers and data loss.
Build a SQL query for a multi-step conversion funnel
Tests your ability to translate a product question into robust SQL. A great answer uses CTEs or left joins to count users at each step, defining the attribution model (e.g., first-touch) and time windows. A red flag is a naive query that double-counts users.
Trade-offs: Bundled Analytics vs. a Warehouse-Native Stack?
This tests your grasp of modern data stack trade-offs: cost, data governance, and flexibility. Discuss the pros of warehouse-native (unified data, lower cost, security) vs. the cons (loss of specialized UI, implementation complexity).
Why do our analytics and backend user counts not match?
This tests your ability to systematically debug data integrity issues. A great answer first defines the metric, then investigates tracking implementation, privacy blockers, and time zone settings. A red flag is blaming one tool without a structured plan.
Client-Side vs. Server-Side Event Tracking
This tests your grasp of data integrity trade-offs. A great answer advocates for server-side tracking for critical events due to its reliability against ad blockers, using client-side only for supplementary UI events. A red flag is treating them as equal.
Architect a Multi-Touch Attribution System
Tests your grasp of data pipeline trade-offs under real-world signal loss. A great answer outlines the pipeline (ingest, store, model), contrasts last-touch (simple state) vs.
Design a User Onboarding Funnel Analysis System
This tests translating a business need into a data model and query. First, define the cohort. Then, use CTEs to find the first timestamp for each event per user. Finally, count users at each step.
Implement an A/B test for a new checkout flow
Tests your grasp of the full A/B testing lifecycle. A great answer outlines a feature flag system, consistent user bucketing via hashing a stable user ID, and an analytics query grouping by variant. A red flag is suggesting simple client-side randomization.
How do you handle the multiple comparisons problem in A/B testing?
Tests your grasp of statistical risk in experimentation. Explain how multiple tests inflate false positives, then describe mitigations like Bonferroni correction or limiting concurrent tests. A red flag is suggesting total test isolation, which is impractical.
Visualize Correlation Between Load Time and Session Duration
Tests your ability to choose the right chart for correlation and layer in additional variables. A great answer starts with a scatter plot (load time vs. session duration), then uses color to represent the network type.
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Set up a cohort analysis for a new onboarding flow
This tests your ability to design a clean experiment to measure product impact. A great answer defines control/treatment cohorts by acquisition date (before/after Jan 1st), picks a specific metric like W1 retention, and compares them.
How to visualize a complex, multi-stage customer funnel?
Tests your ability to choose the right visualization for non-linear user flows. Propose a Sankey or Alluvial diagram to show flow volume, drop-off, and re-entry. A red flag is suggesting multiple simple charts that fail to show the paths between stages.