What is a Time Series?
- Time Series data is a series of data points indexed or listed or graphed with an equally spaced period.
- Time series forecasting is the use of the model to predict future values based on previously observed value.
- Input Past --> Predict future.
Component of Time Series:
- Trend: Increase or decrease over a long period. India GDP
- Seasonal Pattern: Short-term variation occurring due to seasonal factors. Winter sales
- Cyclical Patterns: It is a medium-term variation caused by circumstances, which repeat in irregular intervals. Recession
- Irregularity Patterns: Which Occurs due to unpredictable factors. Anomaly
Where can we not use Time Series?
- If the variable is not dependent on time.
- If Values are constant.
- Values represented using known function as sin(x), cos(x) etc.
- Time Series algorithm cannot be used if data is not stationary.
Time series models:
- ARIMA
- SARIMA
- FARIMA
- LSTM