Table 2.
Unit root test.
| Variable | HT TEST | |||
|---|---|---|---|---|
| Statistic | H0 | P-value | Outcome | |
| ΔzPM | −0.1043 | Panels contain unit roots | 0.0000*** | Smooth |
| Δzln(SO2) | 0.0094 | Panels contain unit roots | 0.0000*** | Smooth |
| Δzln(PGDP) | 0.3925 | Panels contain unit roots | 0.0000*** | Smooth |
| ΔzNHP | −0.6910 | Panels contain unit roots | 0.0000*** | Smooth |
| ΔzPMHS | −0.3638 | Panels contain unit roots | 0.0000*** | Smooth |
| Δzln(PDI) | −0.4800 | Panels contain unit roots | 0.0000*** | Smooth |
| ΔzUR | −0.1425 | Panels contain unit roots | 0.0000*** | Smooth |
| ΔzPAR | −1.2241 | Panels contain unit roots | 0.0000*** | Smooth |
z represents for standardization. *p < 0.1, **p < 0.05,
p < 0.01.