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📈 Data ScientistID: ds-hypothesis-testing-power-analysis

Hypothesis Testing, Type I/II & Power

假设检验、两类错误与功效权衡
🎯Core Definition
Statistical Hypothesis Testing, Type I/II Error Trade-offs & Power Analysis formalizes the decision-theoretic framework for online A/B experimentation; under null hypothesis H0H_0 (treatment effect Δ=0\Delta = 0) versus alternative hypothesis H1H_1 (treatment effect Δ0\Delta \neq 0): 1) Type I Error (α\alpha, False Positive): rejecting true null when no real effect exists, industrially capped at α=0.05\alpha = 0.05; 2) Type II Error (β\beta, False Negative): failing to detect a genuine effect; 3) Statistical Power (1β1 - \beta): the probability of correctly rejecting false null given true effect size δ\delta, industrially targeted at 0.80\ge 0.80 (80%80\%); balancing Type I and II risk governs sample allocation and guards against both reckless feature rollouts and missed revenue growth opportunities.
💡Use Cases
A/B test parameter design, DS foundational statistics screening, and business risk governance.
Key Problems Solved
Eliminates both false-positive feature rollouts that degrade UX and false-negative omissions of winning growth strategies due to undertrained sample sizes.
🎯5 High-Frequency Exam Points
1
Draw the dual probability density curves of H0H_0 and H1H_1 highlighting exact geometric areas corresponding to α/2\alpha/2, β\beta, and Power (1β1-\beta)?
2
Why must product A/B tests enforce Two-Tailed tests even when positive metric lifts are anticipated (protecting against severe regressions)?
3
Contrast Statistical Significance (p<0.05p < 0.05) vs Practical Business Significance (Cohen's dd) under big-data sample regimes?
4
Why does Welch's tt-test serve as the robust default over Student's tt-test under unequal group sizes and heteroscedastic variances?
5
Prove the asymptotic equivalence between the 2-sample proportion ZZ-test and Pearson's Chi-Square Test for binomial ratio metrics?
🔗Foundational Prerequisite Cards (Click to Review)
Updated 2026-08-14
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