MATHEMATICAL ANALYSIS-PREDICTIONS OF INTERNAL GENERATED REVENUE (IGR) IN SOME STATES IN NIGERIA
In this paper, we apply the LINEST model of the Microsoft excel to the population, Nigeria (Naira) exchange rate with US Dollar and Internal Generated Revenue (IGR) of 2014 top-10 Nigerian states by IGR in billions of naira from 2010 to 2014 as in the data bases of National Population Commission (NPC), Central Bank of Nigeria (CBN) and National Bureau of Statistics (NBS) respectively. The indexed IGR is used as proxy for each state and the nation. The last census of 2006 by NPC is used as proxy to the national and states population, and the end of December CBN exchange rate with U.S. Dollar was used as well. The research which results into 14 equations (10 for states and 4 for the nation but all having – and 0) proves that the states in discuss (including Lagos, Rivers, Kaduna and Enugu) over spend/levy, against assets, tax and securities, the members of the states beyond the normal exchange rate in order to meet-up with the IGR target. This is seen in the negative “Difference” of the last/8th column in all the phases’ table of chapter 4; the highest (90%) resulting in 2013 indicated that the nation experienced subsidy removal from fuel at the end of the year in 2013. At the other hand, the positive “Difference” (highest in 2010-70%) indicated that the concerned states submitted an invalid data, indeed below their IGR. The study showed that fuel subsidy removal generates and stimulates excess charges and expenses in the Nigerian economy. The author recommends that Nigeria should maintain subsidy assistance to the member states; charges levied on assets, tax and securities should not exceed the CBN exchange rating. Again, the nation/states in concern should use the formulated equati cons for predicting or estimating the IGR to the dynamic/uncertain exchange rate of Nigeria Naira with US Dollar. The national IGR equation, in billions of naira, is 𝑦 = 35.376𝑥 − 3905.5 .