ab-test-stats

ab-test-stats is a skill for Claude Code, Codex from guia-matthieu/clawfu-skills. It costs 39 tokens per session (1,036 once invoked), scanned A, original, MIT.

A calculator for judging A/B tests, which compare two versions to see whether one performs better than the other by more than random chance.

In plain words
What is it for?
Use it to check statistical significance, plan the number of users needed, estimate test duration, and assess whether a test can detect a meaningful difference.
Why use it?
It helps distinguish a real improvement from a misleading result caused by too little data or normal variation.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to check statistical significance, plan the number of users needed, estimate test duration, and assess whether a test can detect a meaningful difference.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/guia-matthieu/clawfu-skills/ab-test-stats
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add guia-matthieu/clawfu-skills --skill ab-test-stats
Clone the repo
git clone --depth 1 https://github.com/guia-matthieu/clawfu-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for ab-test-stats

README.md
[![agentmods](https://agentmods.dev/badge/skills/guia-matthieu/clawfu-skills/ab-test-stats/github.svg)](https://agentmods.dev/skills/guia-matthieu/clawfu-skills/ab-test-stats)
Your own site
<a href="https://agentmods.dev/skills/guia-matthieu/clawfu-skills/ab-test-stats"><img src="https://agentmods.dev/badge/skills/guia-matthieu/clawfu-skills/ab-test-stats/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for ab-test-stats

Your own site · 80×15
<a href="https://agentmods.dev/skills/guia-matthieu/clawfu-skills/ab-test-stats"><img src="https://agentmods.dev/badge/skills/guia-matthieu/clawfu-skills/ab-test-stats.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 39 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,036 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00039 $0.01036
Opus 5 $0.00019 $0.00518
Sonnet 5 $0.00008 $0.00207
Haiku 4.5 $0.00004 $0.00104

Measured 11d ago against content hash e5ff71348607, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

ab-test-stats scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/main.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/analytics/ab-test-stats/SKILL.md · 149 lines

How it starts

The opening of the file, as written. The whole thing — 149 lines — stays where its author put it; the contents beside it link to each section on GitHub.

A/B Test Statistics Calculator

Calculate statistical significance for A/B tests - know when your results are real, not random chance.

When to Use This Skill

  • Test analysis - Determine if results are statistically significant
  • Sample planning - Calculate required sample size before testing
  • Duration estimation - Know how long to run experiments
  • Power analysis - Ensure tests can detect meaningful differences

What Claude Does vs What You Decide

Claude Does You Decide
Structures analysis frameworks Metric definitions
Identifies patterns in data Business interpretation
Creates visualization templates Dashboard design
Suggests optimization areas Action priorities
Calculates statistical measures Decision thresholds

Dependencies

pip install scipy numpy click

Commands

Check Significance

python scripts/main.py significance --control 1000,50 --variant 1000,65
python scripts/main.py significance --control 5000,250 --variant 5000,300 --confidence 0.99

Calculate Sample Size

python scripts/main.py sample-size --baseline 0.05 --mde 0.02
python scripts/main.py sample-size --baseline 0.10 --mde 0.01 --power 0.90

Estimate Duration

python scripts/main.py duration --traffic 1000 --baseline 0.05 --mde 0.02

Examples

Example 1: Analyze Test Results

# Control: 1000 visitors, 50 conversions (5%)
# Variant: 1000 visitors, 65 conversions (6.5%)
python scripts/main.py significance --control 1000,50 --variant 1000,65

# Output:
# A/B Test Results
# ─────────────────────────
# Control:  5.00% (50/1000)
# Variant:  6.50% (65/1000)
# Lift:     +30.0%
#
# Statistical Analysis
# ─────────────────────────
# p-value:      0.089
# Confidence:   91.1%
# Result:       NOT SIGNIFICANT (need 95%)
#
# Recommendation: Continue test for more data

Example 2: Plan Sample Size

# Baseline 5% conversion, want to detect 20% relative lift (1% absolute)
python scripts/main.py sample-size --baseline 0.05 --mde 0.01

# Output:
# Sample Size Calculator
# ──────────────────────────────
# Baseline conversion: 5.0%
# Minimum detectable effect: 1.0% (20% relative)
# Target conversion: 6.0%
#
# Required per variant: 3,842 visitors
# Total required: 7,684 visitors
#
# At 1000 daily visitors: ~8 days

Read the full file on GitHub · 149 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 11d ago First seen · 149 lines · 39 tokens per session scan A e5ff71348607

Subscribe to this mod's changes

ab-test-stats is a skill published in the GitHub repository guia-matthieu/clawfu-skills (149 stars, last pushed 5mo ago), licensed MIT. It adds 39 tokens to every session and 1,036 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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