Table 4.
Robustness tests for heterogeneity of slopes.
| Equality mean tests |
Equality variance tests |
||||
|---|---|---|---|---|---|
|
Satterthwaite-Welch |
Anova |
Bartlett |
Levene |
Brown-Forsythe |
|
| Gold | |||||
| Whole period | 516.56 [0.000] | 128.41 [0.000] | 0.2444 [0.885] | 0.0398 [0.961] | 0.0437 [0.957] |
| Pre-COVID19 | 133.77 [0.000] | 121.04 [0.000] | 1.1383 [0.888] | 0.4636 [0.761] | 0.4241 [0.789] |
| During COVID19 Outbreak |
91.080 [0.000] |
81.375 [0.000] |
0.7859 [0.852] |
0.6252 [0.608] |
0.3019 [0.823] |
| Brent | |||||
| Whole period | 139.14 [0.000] | 143.82 [0.000] | 2.1693 [0.538] | 1.0275 [0.405] | 0.7801 [0.521] |
| Pre-COVID19 | 392.61 [0.000] | 124.35 [0.000] | 5.5403 [0.236] | 1.6761 [0.204] | 1.5644 [0.231] |
| During COVID19 Outbreak | 150.72 [0.000] | 144.22 [0.000] | 4.0957 [0.393] | 1.5952 [0.223] | 1.1117 [0.385] |
Notes: This table presents the mean equality tests (Satterth-Welch and Anova statistics) and the variance equality tests (Bartlett, Levene, and Brown-Forsythe) for upward and downward Hurst exponents.