do we add seasonality in the ollis regression does ols classify a period or a time series? when do you classify a time series when can a descending time series be classified? what makes a data series as descending how to classify descending time series what is the difference between descending and descending time series why is it so difficult to classify data does it make sense to classify a time series as descending when to classify time series as descending should you classify a period with ols when does it make sense to classify time series when to classify time series using ollis if seasonality is negative what is classifying descending time-series what makes a time series a descending time set does it make sense to classify time series with ols? can you classify time series using ols is it ok to classify a time series? why classify an entire time series as descending when to do descending regression on a timeseries