# 4.5 Statistical Analysis II
[Introduction text]

## Least Square Regression and Line of Best Fit
### What is Linear Regression?
Linear regression is one of the most fundamental techniques in data analysis. It models the relationship between two (or more) variables by fitting a **straight line** that best describes the trend in the data.

Linear regression helps identify proportional relationships, estimate calibration constants, or model linear system responses.


## Least square fitting


## Extrapolation


## Moving average