when a time series is backfilled what is the purpose when do you backfill the city data how to backfill ARIMA is arima an exogenous variable why is it useful to backfill data what is argima data how to backfill arima data why do arima model regress state data what is the data i need to backfill which of the following is a way to use arima data? why use arima to backfill time series what is an example of an arima model how to backfill an arima what type of model would backfill the city data in arima how to make arima models exogenous how to use arima data which r model does the state data backfill? arima data backfill exogenous variable what is arima model used for what is the use of arima data in r