ARMA(p,q) Process Model

Definition

A mixed process that combines Autoregressive (AR) and Moving Average (MA) components. $Z_t={\varphi }_1{Z}_{t-1}+\cdots +{\varphi }_p{Z}_{t-p}+a_t-{\theta }_1{a}_{t-1}-\cdots -{\theta }_q{a}_{t-q}$ where $\{a_t\}$ is white noise. It provides a parsimonious way to model complex time series.