Compute an A/B test p-value by hand
Company: Amazon
Role: Data Scientist
Category: Statistics & Math
Difficulty: medium
Interview Round: Technical Screen
In an A/B test on a game feature, you measure **conversion rate** (binary outcome).
- Control: n₁ = 1000 users, x₁ = 120 conversions
- Treatment: n₂ = 980 users, x₂ = 145 conversions
Tasks:
1) Compute the **two-sided p-value** for the null hypothesis H₀: p₁ = p₂ using a **two-proportion z-test** (show formulas and intermediate values).
2) State whether the result is significant at α = 0.05.
3) (Implementation) Describe how you would compute this p-value in Python **without using SciPy** (you may use `math` only).
Quick Answer: This question evaluates understanding of hypothesis testing for proportions, specifically the two-proportion z-test, p-value computation and interpretation of statistical significance in an A/B test with binary outcomes.