Time Series Analysis of Exchange Rate Nigerian Naira to Us Dollar (1981-2016)

This paper includes an empirical examination of modelling and forecasting time series data of the official Nigerian Naira to US Dollar exchange rate. Monthly data from January 1981 to December 2016 were forecasted using the Box-Jenkins ARIMA approach. The study's goals are to quantify the trend, fit a suitable model, and forecast future exchange rates. The Exploratory Data Analysis such as the time plot, Histogram and box plot were plotted. The trend was also estimated using least square and moving average methods. The seasonal variation and seasonal index were estimated using least square method. The data is then differenced once, plotted and the plot indicated that the process is stationary after the first difference. The ACF and PACF were also examined and ADF confirmed the stationary of the process, model identification then follows. Least square method was employed in other to study the pattern of the trend, the regression model 𝑻̂ 𝒕 = -39.83686386 + 0.535691t shows that as time is progressing there will be an increase in the trend line of about 0.535691. Series of ARIMA were examined and the results shows that ARIMA (1,1,0) has the least AIC of 2642.74. Hence, it is the appropriate model. The diagnostic test was also carried out and the histogram, normal plot of the residual showed that the model fit the data. Hence, the Nigeria exchange rate versus the US Dollar was forecasted for four years (48 months) from January 2017 to December 2020. These forecasts will assist policymakers in both Nigeria and the United States of America in determining the future exchange rate and predicted fluctuation intervals (Nigerian Naira to the US Dollar).