Time Series Basics: Trend, Seasonality and Stationarity

Time series data requires special handling due to temporal dependencies. This lesson covers fundamental concepts for time series analysis.

Time Series Components

The time series decomposition formula splits a series into components:

Loading and Preparing Time Series

Visual Inspection

Time Series Decomposition

Stationarity Tests

The Augmented Dickey-Fuller test statistic:

Null hypothesis: (unit root exists, non-stationary).

Making Series Stationary

ACF and PACF

Autocorrelation Analysis

Key Takeaways

1. Always visualize time series before modeling
2. Test for stationarity using ADF and KPSS tests
3. Use differencing or transformations to achieve stationarity
4. ACF/PACF plots help identify model orders
5. Consider seasonal patterns in decomposition