Time series analysis of daily Nigerian Naira-US Dollar Exchange Rates (DNDER) data is conducted. The time plot reveals a positive trend. Seasonality of order 7 is observed; troughs tend to appear on Mondays and peaks on Fridays. Seasonal differencing once produced a series SDDNDER with a slightly...

The distinction between stationarity, difference stationarity, deterministic trends as well as between short- and long-range dependence has a major impact on statistical conclusions, such as confidence intervals for population quantities or point and interval forecasts. In this paper, recent...

SEMIFAR models introduced in Beran (1999) provide a semiparametric modelling framework that enables the data analyst to separate deterministic and stochastic trends as well as short- and long-memory components in an observed time series. A correct distinction between these components, and in...