What is book5_essentials-of-probability-and-statistics?

This repository is the companion code and notebooks for a Chinese-language textbook on probability and statistics, part of a series called the Iris Book Series. The series is described as bridging basic arithmetic and machine learning, with this particular volume covering statistical concepts. The README is written in Chinese and is very brief. It provides links to a Chinese knowledge-sharing platform where discounted entry points to three related books in the series can be found, covering statistics, mathematics essentials, and matrix topics. There is a short note saying the open-source resources are permanently available, and a mention that readers who report typos or errors may receive a copy of the book as thanks. The repository itself is marked as containing Jupyter Notebooks, which are interactive documents that mix explanatory text with runnable code. Based on the repository name and the series context, the notebooks likely cover probability distributions, statistical inference, regression, PCA (a technique for reducing data complexity), and related topics that feed into machine learning foundations. However, the README does not describe the notebook contents directly, so the specific coverage is not confirmed from the available text.