# Probability Paradox Lab — Math That Defies Intuition > Math That Defies Intuition (iPhone/iPad app by Non Kudo.) - Source: https://appshunter.io/ios/app/probability-paradox-lab/id6782385785 (this page in markdown: same URL + `.md`) - Developer: [Non Kudo](https://appshunter.io/developer/1890455917) - Category: Education, Reference - Price: Free with in-app purchases - Age rating: 4+ - Requires: iOS 16.0 · 13 MB - Languages: American English, French (France), German (Germany), Hindi, Japanese, Korean, Russian, Chinese (Simplified, China), European Spanish - Released: 2026-07-14 - Data updated: 2026-09-06 - User reviews in markdown: https://appshunter.io/ios/app/probability-paradox-lab/id6782385785/reviews.md ## What is Probability Paradox Lab? "With 23 people in a class, what's the chance two share a birthday?" The answer exceeds 50%. Were you surprised? Probability Paradox Lab is an interactive app that lets you experience mathematical paradoxes through simulation — results that feel wrong, yet are mathematically proven. [ HOW IT WORKS ] 1. Make your intuitive guess 2. Run the simulation and see the real result 3. Read the math explanation and understand why Be surprised by the answer. Be surprised again by the explanation. [ FREE THEMES ] Birthday Problem (Free) With just 23 people, the probability of a shared birthday exceeds 50%. Why? Monty Hall Problem (Free) After the host opens a losing door, switching wins 2/3 of the time. Mathematically proven — yet deeply counterintuitive. Two Envelopes Problem (Free) A seemingly valid argument says you should always switch envelopes. Where's the flaw? Coupon Collector Problem (Free) Collecting all 10 kinds takes about 29 pulls on average. Fast at first, then it stalls. [ PREMIUM THEMES ] One-time purchase unlocks 12 more paradoxes and Quiz Mode across all themes. No subscriptions, no ads for premium users. Ellsberg Paradox Why do people prefer known odds over unknown ones — even when the math says they're equal? Boy or Girl Paradox "One child is a boy." How does that single fact change the probability? False Positive Paradox A 99%-accurate test says positive for a disease 1% of people have. You're sick with only ~50% odds. Gambler's Fallacy Five heads in a row. Is tails due? Randomness is clumpier than it looks. St. Petersburg Paradox Expected value is infinite, yet you'd pay little to play. Why? Nontransitive Dice (Efron-style) A beats B, B beats C, C beats A. No die is the strongest. Parrondo's Paradox Two losing games, played in alternation, somehow become a winning strategy. Simpson's Paradox A treatment wins in every subgroup — yet loses overall. How? Secretary Problem Interview one at a time with no going back. The optimal strategy for catching the best. Benford's Law About 30% of naturally occurring numbers start with a 1. A curious statistical bias. Friendship Paradox Your friends have more friends than you — the network bias that makes it true. 100 Prisoners Problem If even one fails, all are executed. Yet one strategy saves everyone about 31% of the time. [ PERFECT FOR ] - Math & statistics enthusiasts - Curious minds who love "why?" - Brain teaser & trivia fans - Students and lifelong learners ## Pricing and in-app purchases Base price: Free. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Premium Unlock Pack | $0.99 | one-time | ## Version history (last 3 releases) ### 1.2 — 2026-09-02 Six new paradoxes are here — 16 themes in total. • Added the Coupon Collector Problem, False Positive Paradox, Gambler's Fallacy, Secretary Problem (37% rule), Benford's Law, and the 100 Prisoners Problem • Every theme's explanation now ends with a 4-choice quiz (16 themes × 3 questions) • Premium exclusive: Quiz Mode, a random 10-question quiz drawn from every theme • Monty Hall now includes a "100 doors" version — even more convincing than with 3 • Filter and sort themes on the home screen by genre or difficulty • Added Hindi Four themes are now free (Birthday, Monty Hall, Two Envelopes, Coupon Collector). Ads still appear only when returning home after a free theme, at the same low frequency as before. ### 1.1 — 2026-08-26 We've added ads so the three free paradoxes can stay free. • Ads appear only when you return home after finishing a paradox • Frequency is kept low: once after your first paradox, then every three • The Unlock All Themes purchase removes ads entirely • Ad privacy settings can now be changed anytime from Settings (EEA) This was designed to stay out of your way. Enjoy all ten counterintuitive paradoxes. ### 1.0 — 2026-07-14 No release notes. ## More apps by Non Kudo - [たたいて・かぶって・そだてて・ジャンケンポン](https://appshunter.io/ios/app/id6761614334) - [なぜログ - 感情と原因の記録分析 -](https://appshunter.io/ios/app/id6767964571) All apps by Non Kudo: https://appshunter.io/developer/1890455917 ## Related topics [sleeping beauty lab](https://appshunter.io/ios/topics/sleeping-beauty-lab) · [paradox](https://appshunter.io/ios/topics/paradox) --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-06.*