# Machine Learning Notes 01

## Introduction of Machine Learning

Posted by Wang Zhihao on 2017-03-11

## What is Machine Learning

Arthur Samuel (1959). Machine Learning: Field of study that gives computers the ability to learn without being explicitly programmed.

Tom Mitchell (1998) Well-posed Learning Problem: A computer program is said to learn from experience E with respect to some task T and some performance measure P, if its performance on T, as measured by P, improves with experience E.

• T: 将邮件按照正常邮件/垃圾邮件来分类。
• E: 观察你标记垃圾邮件的行为。
• P: 正确被标记为正常邮件/垃圾邮件的个数/占比。

## 监督学习(Supervised learning)

• 回归(Regression)
• 连续变量（比如预测房屋价格）

• 分类(Classification):
• 不连续变量（比如判断癌症良性/恶性）