Table 1.

ARMA (1, 1) model parameter estimates

Variable	Coefficient	Standard error	T-statistics	Probability
AR (1)	0.999851	0.004673	213.985	2.00E−16
MA (1)	0.518176	0.077013	6.728	1.72E−11

Source: result from analysis of data, 2014. ${\mathit{\sigma }}^2$ = 0.0002664, conditional sum of squares = 0.04, AIC = −899.97.