You have to integrate the time series I before applying the ARMA modell. This means ARMA(0,0), but now have a closer look what ARIMA(0,0,0) means. So the ARMA(0,0) model is made up of two parts:
An ARMA(0,0) modell is shown in the next equtation. Hence an ARMA(0,0) modell is the same as an AR(0) (Autoregressive model of order 0) model or an MA(0) Moving average modell of order 0 modell. Let us have a look at how an ARMA(p,q) (Autoregressive-Moving-Average) modell is structured. ARIMA(0,0,0) can often appear in time series.
