A/B Testing and Causal Inference: Core Concepts and Practice
Scenario
You are a data scientist interviewing for a role working on an online product. You are asked to demonstrate practical A/B testing and causal inference knowledge.
Task
Provide concise, accurate explanations and practical guidance for the following:
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P-value: What it represents and common misinterpretations.
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Errors: Define Type I and Type II errors; relate to power.
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Experimentation Workflow: Outline an end-to-end process from hypothesis to decision, including sample size, segmentation, and variance considerations.
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Simpson's Paradox: Define, give a practical example, and explain how to detect and handle it.
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Metrics: Propose primary and secondary/guardrail metrics for an online product experiment.
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Causal Inference Without Randomization: Name two useful methods and when you would apply each.
Hints to address: hypothesis clarity, sample-size (power) calculation, segmentation, lift vs variance, DAGs or matching, and practical examples.