When you have a set of data points you can adjust a line to them with a regression.

In a **linear regression** a line is adjusted to the points and the **slope** and **interception** of the line is calculated.

If you use Excel you may like to use also this free addon

It creates graphs of the linear regression with a 95% confidence interval.

## Analysis of linear regression

The quality of the adjustment can be seen from the plot or from values of R^2.