Table 4.
ADF unit root tests for monthly visitor arrivals by air transport to New Zealand (January 1993‒December 2013).
| Countries | Constant only |
Constant and trend |
||
|---|---|---|---|---|
| ln(visitors) | Δln(visitors) | ln(visitors) | Δln(visitors) | |
| Australia | −1.27 | −6.04*** | −0.78 | −6.09*** |
| Canada | −1.52 | −8.76*** | −0.02 | −37.36*** |
| China | −2.46 | −5.81*** | −2.05 | −6.05*** |
| Germany | 0.13 | −7.27*** | −2.06 | −7.64*** |
| Japan | −0.22 | −7.08*** | −1.92 | −7.18*** |
| South Korea | −3.32** | −3.85*** | −3.31* | −3.82** |
| United Kingdom | −1.89 | −9.70*** | 0.44 | −11.02*** |
| United States | −1.54 | −6.59*** | −0.81 | −6.69*** |
Remarks: All the time series above are stated in natural logarithm. Δ denotes the first differencing. The values stated above are t-statistics for the ADF unit root tests. *, ** and *** indicate that the explanatory variable is significant at the 0.10, 0.05, and 0.01 significance level, respectively.