Covariance stationary

A stationary time series has statistical properties or moments (e.g., mean and variance) that do not vary in time. Stationarity, then, is the status of a stationary time series. Conversely, nonstationarity is the status of a time series whose statistical properties are changing through time .

Stationarity means that the statistical properties of a time series (or rather the process generating it) do not change over time. Stationarity is important because many useful analytical tools and statistical tests and models rely on it .20 Ağu 2019

The observations in a stationary time series are not dependent on time. Time series are stationary if they do not have trend or seasonal effects . Summary statistics calculated on the time series are consistent over time, like the mean or the variance of the observations.30 Ara 2016