ab-test-setup

Plan and implement statistically valid A/B tests with hypothesis frameworks and sample size calculations.

Updated Feb 5, 2026
One-click install
npx skills add https://github.com/binhnndigital/batch-watermark --skill ab-test-setup-binhnndigital
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: ab-test-setup
Source: https://github.com/binhnndigital/batch-watermark/tree/main/skills/ab-test-setup
Command: npx skills add https://github.com/binhnndigital/batch-watermark --skill ab-test-setup-binhnndigital

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires scipy.

What problem does it solve? Designing A/B tests without statistical rigor leads to false positives, wasted traffic, and wrong product decisions. This Skill guides you through hypothesis formulation, sample size calculation, variant design, and result analysis so your experiments produce trustworthy, actionable outcomes. ## Core Features & Use Cases - Hypothesis Framework: Structure test ideas using the observation-change-effect-audience-metric format to ensure every test has a clear, measurable prediction. - Sample Size & Duration Planning: Calculate required traffic per variant using baseline conversion rate, minimum detectable effect, and statistical power, with included Python scripts for programmatic calculation. - Test Execution & Analysis Guidance: Follow pre-launch checklists, avoid peeking pitfalls, select primary/secondary/guardrail metrics, and interpret results with confidence intervals and segment analysis. - Use Case: You want to test a new headline on your pricing page. The Skill helps you write a strong hypothesis, determine you need 12,000 visitors per variant at a 3% baseline, set up a 50/50 split in PostHog, and analyze the Chi-Squared significance of the results. ## Quick Start Ask the AI to help you plan an A/B test for your landing page, including the hypothesis, required sample size, and metrics to track.

Frequently Asked Questions about ab-test-setup

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I calculate sample size for an A/B test?

Sample size depends on your baseline conversion rate, minimum detectable effect, significance level (usually 95%), and statistical power (usually 80%). Use the included Python script with scipy, or calculators like Evan Miller's, to compute the required visitors per variant.

How long should I run an A/B test?

Run the test until you reach your pre-calculated sample size, typically one to two full business cycles (one to two weeks minimum). Avoid stopping early when results look significant, since peeking inflates false positive rates.

What is the difference between A/B testing and multivariate testing?

A/B testing compares two versions with a single change, making results easy to attribute. Multivariate testing combines multiple changes simultaneously to test interactions, but requires significantly more traffic and more complex analysis.

Should I use client-side or server-side A/B testing?

Client-side testing with JavaScript tools like PostHog or VWO is fast to implement and suits marketing pages, but can cause flicker. Server-side testing renders variants before page load, eliminating flicker, and fits product features or performance-sensitive pages.

Why is my A/B test result not statistically significant?

Insignificant results usually mean insufficient sample size, too small an effect to detect, or a change too subtle to move behavior. Either run the test longer, increase traffic, or design a bolder variant with a larger expected effect.