why would you want to add residual error in an ARIMA? when to use residual residuals in arima can you make a difference when a regression model has been fit how to tell which regression models are stationary can a regression model account for residual error how to difference in regression model can we differ a time series model if a stationary trend is not account for what is the difference between a time series and a regression model what is difference after fitting a regression model can i difference regression analysis after a period why does a regression model need to be different when a stationary data set is included can regression model account for non stationary trend when do i fit a stationary regression model can a time series model account for residuals what is the difference between regression and rima why is it necessary to use regression model to account for residual errors? how to tell if the residual in a regression is stationary can you differ regression models what does the residuals of the regression model mean when the residuals are not stationary in terms of regression models? difference between model and regression