Your question is Sample Size for Statistical Significance. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
How do you determine the required sample size to reach statistical significance?
Explain how you would translate a business-relevant minimum detectable effect into a sample-size requirement for an online A/B test. Your response should address the baseline metric rate or variance, significance level, statistical power, one-sided versus two-sided testing, unit of randomization, available traffic, duration, and practical decision criteria.
Show the calculation with explicit assumptions, define a primary metric and guardrails, and describe how you would validate the result and avoid common experimentation errors.
