Calculate probability for A/B test results
Last updated: February 4, 2026
Quick Overview
Given the following scenario about user conversion, calculate the the p-value.
Meta
Statistics & Math
Data Scientist
Meta
February 4, 2026Data Scientist
Phone Screen
Statistics & Math
Easy
12
5
3,078 solved
Given the following scenario about user conversion, calculate the the p-value.
Meta values data-driven decision making. This Phone Screen question assesses whether you can design experiments, interpret results correctly, and avoid common statistical pitfalls like p-hacking or Simpson's paradox.
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
Hypothesis testing (H0, H1, p-values)
Power analysis and sample size calculation
Conditional probability and Bayes theorem
Causal inference basics
Central Limit Theorem
Multiple testing correction (Bonferroni, FDR)
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
- How would you explain this result to a non-technical audience?
- How would you handle multiple comparisons?
- What if the sample size is very small?
- What assumptions does this test make, and how would you validate them?
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Browse Statistics QuestionsSample Answer
Problem Formulation
In this A/B test scenario, we need to assess user conversion rates between two groups: Group A (control) and Group B (treatment). We can define our hypotheses as follows:
- Null Hypothesis (H0): Ther...
Solution Approach
To calculate the p-value, we follow these steps:
- Collect data on the number of conversions and total users for both groups.
- Calculate the observed conversion rates: and .
- U...
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