Design an A/B test for a recommendation algorithm
Last updated: January 19, 2026
Quick Overview
Design an experiment to test the impact of a redesigned homepage. Include sample size calculation, metrics, and analysis plan.
xAI
January 19, 202618
5
3,777 solved
Design an experiment to test the impact of a redesigned homepage. Include sample size calculation, metrics, and analysis plan.
This statistics question from xAI's Technical Screen tests your ability to apply mathematical reasoning to practical problems. The interviewer expects precise definitions, correct methodology, and awareness of assumptions and limitations.
What the Interviewer Expects
- State the correct formula or theorem with clear definitions
- Apply the concept to the given scenario step by step
- Interpret the result in plain language
- Identify assumptions and when they might be violated
Key Topics to Cover
How to Approach This
- Define your hypotheses (H0 and H1) clearly before performing any test.
- Calculate required sample size BEFORE running an experiment, using power analysis.
- Remember the Central Limit Theorem: sample means become approximately normal with large n.
- Watch for Simpson's paradox. Always segment data by key dimensions.
- Distinguish between statistical significance and practical significance.
Possible Follow-up Questions
- What alternative statistical method could you use here?
- How would you explain this result to a non-technical audience?
- How would you handle multiple comparisons?
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Browse Statistics QuestionsSample Answer
Problem Formulation
To design an A/B test for the redesigned homepage of xAI, we need to establish a clear hypothesis and the metrics we will analyze.
Hypothesis: The redesigned homepage increases the click-through...
Solution Approach
- Determine the baseline CTR: We need the current CTR of the original homepage. Assume it is 5% (0.05).
- Expected improvement: Let’s say we expect the redesigned homepage to improve the CT...
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