A/B Test Plan & Readout

Help me plan and later read out an A/B test. Change being tested: {{change}}. Primary goal metric: {{metric}}. Baseline rate: {{baseline}}. Traffic per week: {{traffic}}. Smallest improvement worth acting on: {{mde}}.

Provide: a hypothesis; primary, secondary and guardrail metrics; sample size and duration reasoning with assumptions shown (and a reminder to confirm with a calculator); randomization and exclusion rules; common pitfalls (peeking, novelty effects, multiple comparisons, sample ratio mismatch); the decision rule defined before launch; and a results template. If I paste results, interpret them cautiously, state the uncertainty and avoid over-claiming.