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Hypothesis and Test Planning Questions

End to end practice of generating clear testable hypotheses and designing experiments to validate them. Candidates should be able to structure hypotheses using if change then expected outcome because reasoning ground hypotheses in data or qualitative research and distinguish hypotheses from guesses. They should translate hypotheses into experimental variants and choose the appropriate experiment type such as A and B tests multivariate designs or staged rollouts. Core skills include defining primary and guardrail metrics that map to business goals selecting target segments and control groups calculating sample size and duration driven by statistical power and minimum detectable effect and specifying analysis plans and stopping rules. Candidates should be able to pre register plans where appropriate estimate implementation effort and expected impact specify decision rules for scaling or abandoning variants and describe iteration and follow up analyses while avoiding common pitfalls such as peeking and selection bias.

HardSystem Design
68 practiced
Design an internal experimentation platform that supports web and mobile A/B tests at 1B monthly users. Describe key components: SDKs, metadata store, bucketing, telemetry ingestion, metric computation, real-time vs batch pipelines, experimentation console, and safety mechanisms. Identify the major trade-offs and monitoring needs.
HardTechnical
97 practiced
You're a BI lead and discover that several past experiments were reported without pre-registration and had interim peeking. Stakeholders have lost trust. Propose a 6- to 12-month roadmap to improve experimentation governance, tooling, and culture. Include measurable success metrics to rebuild trust.
MediumTechnical
68 practiced
You observe a statistically significant 3% lift in sign-ups but a 6% drop in weekly retention (statistically significant). Draft a decision rule on whether to roll out the variant, run follow-up experiments, or abandon it. Include primary/secondary metrics, thresholds, and immediate investigative steps you would take using BI reports.
HardTechnical
74 practiced
Propose a plan to estimate heterogeneous treatment effects using uplift modeling for marketing targeting. Choose modelling approaches (e.g., causal trees, causal forests, meta-learners), describe validation strategy (cross-fitting, RCT holdouts), evaluation metrics (Qini, uplift AUC), and how to operationalize the model in a targeting pipeline.
HardTechnical
74 practiced
Design pseudo-code or an algorithm sketch for applying an online Benjamini-Hochberg-like FDR correction to daily p-values streaming from segmented tests. Discuss data structures, computational cost, and how to ensure FDR control over time in practice.

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