What is Stationarity in Time Series Analysis?

What is Stationarity in Time Series Analysis?

Stationarity in Time Series is one of the common assumptions in many of the time series analysis techniques. A stationary time series (or the underlying process) has mean, variance, and autocorrelation structure that do no change over time. Visually, a stationary time series will be a flat looking series, without trend, constant variance over time, a constant autocorrelation structure over time and no periodic fluctuations. In real-life scenarios lot of […]

Linear Mixed Models

Linear Mixed Models

The Linear Mixed Models procedure expands the general linear model so that the error terms and random effects are permitted to exhibit correlated and non-constant variability. The linear mixed model, therefore, provides the flexibility to model not only the mean of a response variable, but its covariance structure as well. In other words, it is an extension of the general linear model, in which factors and covariates are assumed to […]