Design an A/B test for a pricing model
Last updated: September 11, 2025
Quick Overview
Design an experiment to test the impact of a redesigned homepage. Include sample size calculation, metrics, and analysis plan.
Postmates
September 11, 202563
8
712 solved
Design an experiment to test the impact of a redesigned homepage. Include sample size calculation, metrics, and analysis plan.
This statistics question from Postmates'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
- Set up the problem formally with proper notation
- Apply the correct statistical test with clear justification
- Interpret results with appropriate caveats and confidence levels
- Discuss practical significance vs statistical significance
- Identify potential confounders and how to address them
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 assumptions does this test make, and how would you validate them?
- How would you design a follow-up experiment based on these results?
- How would you handle multiple comparisons?
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Browse Statistics QuestionsSample Answer
Problem Formulation
To test the impact of a redesigned homepage on user engagement and conversion rates, we will set up an A/B test where:
- Group A (Control): Users see the current homepage.
- Group B (Treatment...
Solution Approach
- Define Metrics: We will focus on Conversion Rate (CR) as our primary metric.
- Sample Size Calculation: We will perform a power analysis to determine the required sample size to detect a m...
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