why do process observations have negative values in state space model when do negative values occur in a state model what model fits a process of positive observations? how to simulated an ARMA process which parameters in a state space model must be strict why do negative state space models occur which model has strict positive values why does a state space model always have negative values what is a state-space model for positive process values what model has strict positive parameters what is the condition of positive state space models what is state space why do you find parameters that fit a process of positive data in a state space model how does a state space model work why does a state space model have a negative value which statement should be correct about a state space model? if a process has strict positive values what should the state space model be why do state space models have negative values why do positive values occur in state space models why do process observations have a strict positive value