The purpose of this tutorial is to show a simple technique to estimate periodicity in time series, called **autocorrelation**.

- Introduction
- The Correlation Coefficient
- Autocorrelation Function
- The Code
- The Correlogram
- Conclusion

This tutorial is part of a longer series that focuses on how to analyse time series.

- Part 1. An Introduction to Signal Smoothing
- Part 2. Time Series Decomposition
**Part 3. The Autocorrelation Function**