The random coefficient autoregressive model has been utilized for modeling financial time series because it possesses features that are often observed in financial time series. When the mean of the random autoregressive coefficient is one, it is called the stochastic unit root model. This paper...

A recursive formula for computing the exact value of score vectors is proposed, which is more desirable than approximate values in some statistical analyses, for a general form of the linear Gaussian state space model. Unlike most extant methods, our formula calculates all components of the...