AB STRACT

 • This study is born to construct a suitable statistical time series model for monthly sales of crude oil exportation in Nigeria. The data used for this work is a secondary data collected from Nigerian National Petroleum Corporation (NNPC) Annual statistical bulletin (ASB). It spans from 2002 to 2011. Box and Jenkins method and approach of time series was adopted as a tool for the analysis. The trend was estimated which indicates an upward long term movement of monthly sales of crude oil exportation. The plots of autocorrelation function and partial autocorrelation function of the differenced data were used to identify a suitable model for the data. By the use of statistical software called MINITAB, an Autoregressive integrated moving average (ARJMA) model was fitted and diagnostic checking was done using Q statistics to check the adequacy of the fitted model. Forecast values were also made for the period of 24 months (2 years). It was revealed that monthly sales of crude oil exportation in Nigeria have no seasonal influence. As such the study recommends that priority should be accorded to the boosting of the current level of oil output which may involve rehabilitation of abandoned firms, establishment of new ones, and provide appropriate incentives as a means of sustaining exportation levels