In this paper, the Nigerian External Reserve (ER) for the period 1960 – 2010 was modeled using descriptive time series technique and Box-Jenkins (ARIMA) model. Prior to the analysis the logarithm transformation was found to be the most appropriate to stabilize the variance of the data after the Bartlett's test of homogeneity of variance suggested non-constant variance. Applying the descriptive time series technique on the transformed data, a linear trend was found adequate which suggest an exponential trend for the untransformed data. However, the seasonal indexes were found to be insignificant which implies that the data is completely dominated by the trend. Furthermore, considering that the model obtained using the descriptive time series technique was found inadequate as suggested by the autocorrelation function (ACF) of the irregular component and therefore cannot be used for forecasting, a Box-Jenkins model was then fitted and was found adequate as suggested by the p-value = 0.00 for the modelsignificance. Furthermore using the Relative Percentage Change (RPC) to assess the impact ofthe various regimes on the ER data, it was found that the regimes of General Yakubu Gowon (Rtd) and Alhaji Shehu Shagari respectively had the most positive and negative impact on the ER data. Finally using the cumulative RPC in assessing the impact of civilian and military regimes on the ER data, it was discovered that the military had a higher positive impact than the civilian regimes.
Bulletin of Mathematical Sciences and Applications (Volume 3)
J. Ohakwe et al., "A Statistical Analysis of the Nigerian External Reserveand the Impact of Military and Civilian Rule", Bulletin of Mathematical Sciences and Applications, Vol. 3, pp. 49-62, 2013