The short run relationship between foreign direct investment and selected macroeconomic variables of real gross domestic product, exchange rate, inflation rate and interest were assessed with the aid of the ARDL methodology. The result of the ARDL approach as presented in Tables 24, 25, 26 and 27 were interpreted using the relative coefficient of the variables, adjusted R- square, Durbin Watson statistic for autocorrelation and f-statistic and its p-value.
4.7.1 Real Gross Domestic Product and Foreign Direct Investment
From Table 24, lagging the independent variable by one year shows that there is a positive significant relationship between foreign direct investments and real gross domestic product in Nigeria. The essence of lagging the FDI by one year is that it allows varying amount of recent trend in FDI to be brought in the forecast. The coefficient of the constant 1319226 implies that real gross domestic product would be ₦1, 319, 226 million if foreign direct investment inflow is kept constant. As shown by the foreign direct investment coefficient of 3.294426, a unit increase in foreign direct investments results in
₦3.29 million increase in real gross domestic product. From the Adjusted R-squared, 99.74% variation in real gross domestic product was explained by changes in foreign direct
investment inflows. The p-value of the F-statistic unveils that the variation in real gross domestic product significantly refl ect ed on the foreign direct investments within the period studied. Durbin Watson of 1.97 is quite close to the bench mark of 2.0 thus there is no autocorrelation problem in the model as estimated.
Table 24: ARDL Regression Result for RGDP and FDI
Variable Coefficient Std. Error t-Statistic Prob.
RGDP(-1) 1.706985 0.177122 9.637353 0.0000 RGDP(-2) -0.762803 0.180964 -4.215213 0.0002 FDI -0.907947 1.004088 -0.904250 0.3733 FDI(-1) 3.294426 1.016978 3.239426 0.0030
C 1319226. 447299.0 2.949315 0.0062
R-squared 0.997787 Mean dependent var 32735713
Adjusted R-squared 0.997482 S.D. dependent var 18212452 S.E. of regression 913875.3 Akaike info criterion 30.42383 Sum squared resid 2.42E+13 Schwarz criterion 30.64829 Log likelihood -512.2051 L Hannan-Quinn criter. 30.50038
F-statistic 3269.301 Durbin-Watson stat 1.972288
Prob (F-statistic) 0.000000 Source: Data output via E-views 9.0
4.7.2 Exchange Rate and Foreign Direct Investment
As can been seen in Table 25, foreign direct investment inflows has a positive and significant relationship with exchange rate. Looking at the constant coefficient of 6.302032, if the foreign direct investment inflow is kept constant, exchange rate would be
₦6.30. Similarly, a percentage rise in foreign direct investment leads be ₦3.28 appreciation in exchange rate. From the adjusted R-squared value it has been shown that 95.58%
changes in exchange rate was attributed to inflow foreign direct investment.
Furthermore, variation in exchange rate significantly accounted for the level of foreign direct investment inflows in Nigeria. The Durbin Watson value of 1.79 is within the acceptable range signifying that there is no danger of autocorrelation in the model.
Table 25: ARDL Regression Result for EXCHR and FDI
Variable Coefficient Std. Error t-Statistic Prob.
EXCHR(-1) 0.978900 0.081101 12.07020 0.0000
FDI 3.28E-05 1.71E-05 1.920620 0.0463
FDI(-1) -3.01E-05 2.01E-05 -1.502431 0.1455
FDI(-2) -4.09E-05 2.33E-05 -1.755233 0.0915
FDI(-3) -5.17E-06 2.19E-05 -0.235639 0.8156
FDI(-4) 5.78E-05 1.93E-05 3.000908 0.0060
C 6.302032 4.276599 1.473608 0.1531
R-squared 0.964320 Mean dependent var 86.08086
Adjusted R-squared 0.955757 S.D. dependent var 70.87116 S.E. of regression 14.90703 Akaike info criterion 8.432183 Sum squared resid 5555.490 Schwarz criterion 8.752813 Log likelihood -127.9149 L Hannan-Quinn criter. 8.538463
F-statistic 112.6130 Durbin-Watson stat 1.797739
Prob (F-statistic) 0.000000 Source: Data output via E-views 9.0
4.7.3 Inflation Rate and Foreign Direct Investment
The regression result in Table 26 shows that inflation rate has an insignificant negative relationship with foreign direct investment. The coefficient of the constant depicts inflation rate to be 15.51% assuming the inflow of foreign direct investment is constant. A unit appreciation in foreign direct investment entails a 9.38% reduction in inflation rate. Considering the adjusted R- squared coefficient, 40.60% variation in inflation rate was owed to fluctuation in foreign direct investment inflows. Thus, inflation rate was significantly responsible for variation in foreign direct investment as evidenced by p-value (0.00) of the f-statistic which is significant at 5% level of significance. There is no problem of autocorrelation in the model as the Durbin Watson value is 1.86 is very close to 2.0 which is a suggestion that the variables in the model are free from autocorrelation.
Table 26: ARDL Regression Result for INFR and FDI
Variable Coefficient Std. Error t-Statistic Prob.
INFR(-1) 0.708519 0.169504 4.179947 0.0002 INFR(-2) -0.313431 0.171280 -1.829936 0.0772 FDI -9.38E-06 5.77E-06 -1.625466 0.1145
C 15.54293 5.045974 3.080264 0.0044
R-squared 0.460007 Mean dependent var 19.62676
Adjusted R-squared 0.406007 S.D. dependent var 17.38151 S.E. of regression 13.39609 Akaike info criterion 8.137934 Sum squared resid 5383.656 Schwarz criterion 8.317505 Log likelihood -134.3449 L Hannan-Quinn criter. 8.199173
F-statistic 8.518742 Durbin-Watson stat 1.866836
Prob (F-statistic) 0.000304 Source: Data output via E-views 9.0
4.7.4 Interest Rate and Foreign Direct Investment
The regression output in Table 27 lays credence to the presence of a negative insignificant relationship between interest rate and foreign direct investment. The constant coefficient of 7.522773 is an indication that interest rate will experience 7.52% growth if foreign direct investment is kept constant. Each time foreign direct investment increases by a unit, interest rate declines by 1.25%. The revelation from the adjusted R-squared shows that changes in interest rate accounted for only 31.76%
changes in foreign direct investment, and this is statistically significant based on p-value (0.00) of f-statistic (6.12). The Durbin Watson value of 2.1 is a clear evidence of no autocorrelation in the model.
Table 27: ARDL Regression Result for INTR and FDI
Variable Coefficient Std. Error t-Statistic Prob.
INTR(-1) 0.312341 0.171021 1.826329 0.0778 INTR(-2) 0.308802 0.159336 1.938049 0.0621 FDI -1.25E-06 1.44E-06 -0.873330 0.3894
C 7.522773 2.814118 2.673226 0.0120
R-squared 0.379709 Mean dependent var 18.09853
Adjusted R-squared 0.317680 S.D. dependent var 4.378817 S.E. of regression 3.617019 Akaike info criterion 5.519309 Sum squared resid 392.4849 Schwarz criterion 5.698880 Log likelihood -89.82825 L Hannan-Quinn criter. 5.580548
F-statistic 6.121468 Durbin-Watson stat 2.132639
Prob (F-statistic) 0.002241 Source: Data output via E-views 9.0