// StatPlay
An interactive visualization tool for experiencing statistical concepts firsthand. Not a replacement for textbooks, but a device for those "if only I could see it move, I'd get it instantly" moments.
Calculation practice and systematic study are left to textbooks and problem sets. All this tool can do is create experiences that build understanding through imagery. If it makes you think "statistics is actually interesting," that's enough.
Content is structured with reference to the following:
- Yasuhiko Torii, Introduction to Statistics (はじめての統計学), Nikkei Publishing
- Hiroyuki Kojima, A Completely Self-Taught Introduction to Statistics (完全独習 統計学入門), Diamond, Inc.
- Japan Statistical Society, ed., Grade 2 Statistical Examination Official Problem Collection (CBT Edition), Jitsumu Kyoiku Shuppan
All code is open source. Feel free to modify and use for education. Commercial use is governed by the CC BY-NC 4.0 license — please get in touch first.
© 2026 Sasai Lab
// How This Tool Came to Be
While studying for the Grade 2 Statistical Examination, I got stuck on standardizing to the normal distribution. I thought I understood, but couldn't actually picture it. I kept wishing something like this existed.
"If I could just see it move, I'd get it instantly" — I was convinced that interactive experience is what transforms concept understanding in an instant.
The thing is, I had no skills to implement interactive visualizations on the frontend. I'm a direction/management person, not a professional coder. Before, this story would have ended at "I want to build it but can't." AI happened to come along as an option, and that made it possible.
AI writes the code. But what to build — that's the human's call. When you've done direction work, you can tell from watching the terminal when something looks reckless or high-risk. Is this design correct? Will it survive future extensions? Is this feature really necessary? More importantly, if you don't understand the statistical theory correctly, you can't see "what to make move so it clicks." You can't build something correctly if you don't understand it yourself. That's what I learned firsthand.
Building itself was the greatest learning experience.
The more I learn, the more I want to build. And figuring out how to make it move gets ever more challenging.
Statistics is actually really fascinating.
// Creator
Jumpei Sasai / 笹井淳平
Started my career as a systems engineer at NTT, then directed game, web service, and app development at Square Enix and Drecom. Discovered the fascination of statistics while studying for the Grade 2 Statistical Examination, and built this tool. There's still so much to learn, but building while learning seems to suit me.