# Notion - (Best approximation|Closest|Closeness)

### Table of Contents

## 1 - About

This notion of “best approximates” comes up again and again:

- in least-squares, a fundamental data analysis technique,
- image compression,
- in principal component analysis, another data analysis technique, and
- in latent semantic analysis, an information retrieval technique.

## 2 - Articles Related

Advertising