Table 4.
The result of robustness test (bootstrapping times = 5,000, N = 1,548).
| Methods | Effect | Values of NTB | Standardized estimate | S.E. | 95% confidence interval | |
|---|---|---|---|---|---|---|
| LLCI | LLCI | |||||
| Robustness test 1 | Total effect | – | 0.073 | 0.021 | 0.031 | 0.114 |
| Direct effect | – | 0.052 | 0.020 | 0.013 | 0.091 | |
| Indirect effect | –SD = 2.849 | 0.041 | 0.012 | 0.019 | 0.065 | |
| M = 3.333 | 0.020 | 0.008 | 0.005 | 0.035 | ||
| +SD = 3.817 | −0.002 | 0.011 | −0.022 | 0.019 | ||
| Robustness test 2 | Total effect | – | 0.073 | 0.019 | 0.036 | 0.110 |
| Direct effect | – | 0.053 | 0.018 | 0.018 | 0.088 | |
| Indirect effect | –SD = 2.849 | 0.024 | 0.009 | 0.008 | 0.042 | |
| M = 3.333 | 0.015 | 0.006 | 0.004 | 0.027 | ||
| +SD = 3.817 | 0.006 | 0.009 | −0.012 | 0.023 | ||
Robustness test 1 refers to the method of replacing the CNC with the NNC; robustness test 2 refers to the method of deleting the data of “Hubei” and “Tibet”; –SD, M, +SD, respectively, represent the value of NTB is one standard deviation lower than the average, equal to average, and one standard deviation higher than the average.