TS Basics

Time Series Basics Q&A

1What is a time series?
Answer: Ordered observations indexed by time.
2Components of time series?
Answer: Trend, seasonality, cyclic pattern, and noise.
3What is stationarity?
Answer: Statistical properties remain constant over time.
4Why stationarity important?
Answer: Many forecasting methods assume stable mean/variance.
5How test stationarity?
Answer: ADF/KPSS tests plus visual diagnostics.
6What is differencing?
Answer: Subtracting previous values to remove trend/non-stationarity.
7Lag feature meaning?
Answer: Past value used as predictor for current/future value.
8Train/test split for time series?
Answer: Chronological split; never shuffle.
9Common TS metrics?
Answer: MAE, RMSE, MAPE, sMAPE.
10One-line summary?
Answer: Time series modeling respects temporal order and dependency.