A weaker form of stationarity compared to strict stationarity. A time series process is said to be second-order stationary if the mean and the autocovariance structure are constant over time, but its variance may still change over time.
A weaker form of stationarity compared to strict stationarity. A time series process is said to be second-order stationary if the mean and the autocovariance structure are constant over time, but its variance may still change over time.