Generalized Autoregressive Conditional Heteroskedastic Model to Examine Silver Price Volatility and Its Macroeconomic Determinant in Ethiopia Market

Table 2

The ADF and PP unit root tests at level and first differenced for the series.

Variables	ADF test		PP test		First differenced
	t-Statistic	value	t-Statistic	value	ADF test	PP test
					t-Statistic	t-Statistic
Crude oil	−1.512	0.525	−1.282	0.637	−9.426	−9.408
Exchange rate	1.93213	0.999	1.7948	0.999	−12.019	−12.019
General inflation rate	1.599841	0.999	2.1324	0.999	−5.121	−8.648
Inflation rate of food items	0.66696	0.991	1.2221	0.998	−6.107	−9.921
Inflation rate of nonfood items	2.218027	1.00	4.2888	1.000	−3.727	−10.862
Saving interest rate	−1.83399	0.363	−1.837	0.361	−13.767	−13.767
Price return series of silver	−8.30578	0.000	−13.99	0.000	—	—

Significant at 1% level of significance.