Table 6 The result in Table 6 shows the acceptance of the null hypothesis of the four assumptions diagnosed. That is the residuals from the model are normally distributed with a constant mean and variance and are not autocorrelated since the probability values of the test statistics are not significant at the 5 percent level. Also, it was revealed that the model was correctly specified which indicates that there is no specification bias. Figure | and 2 are aimed at examining whether any of the estimated coefficients falls outside the cycles. If any of the coefficients falls outside the circle then, the coefficient estimated is not stable. The results from figure | and 2 show that none of the coefficient falls outside the CUSUM and CUSUM square circle at 5% level, hence the parameters estimated are stable.