Article
M Process is indicated by MA(q) is believed to be a general finite order procedure that is an autoegressive version of a stationary sequence with covariance. It is stationary in the sense that the current conditional expectation is dependent on only a function of the current and lagged unknown shocks. This function is known as the partial autocorrelation function.
MA(q) MA(q) does not have an unique MA polynomial, as opposed to AR processes. There are many MA(q), lag operator polynomials which may be stationary and share the same asymptotic property.
In order to ensure that the process is causal, it is common to impose invertibility restrictions on the MA polynomial. This ensures that events from the past (and not future ones) are the only ones that can predict the current events.