Table 1. Predicted and observed number of exotic plant species in the Canadian provinces and other nations.
| Country and province (ref.) | Predicted no. of exotic plant species (prediction interval) | Observed no. of exotic plant species |
|---|---|---|
| Australia (14) | 2,490 (1,908-3,249) | 1,952 |
| Canada (22) | ||
| Alberta | 426 (326-555) | 301* |
| British Columbia | 763 (585-996) | 691 |
| Manitoba | 363 (278-474) | 321 |
| New Brunswick | 540 (414-704) | 469 |
| Newfoundland | 402 (308-525) | 371 |
| Nova Scotia | 580 (444-756) | 522 |
| Ontario | 1,017 (779-1,327) | 914 |
| Prince Edward Island | 367 (281-479) | 312 |
| Quebec | 899 (689-1172) | 703 |
| Saskatchewan | 340 (260-444) | 281 |
| New Zealand (45) | 1,231 (943-1,606) | 1,570 |
| Puerto Rico (22) | 997 (764-1,301) | 758* |
| United Kingdom (15) | 1,383 (1,060-1,804) | 1,169 |
We obtained the predicted number of exotic species and prediction intervals by using standardized parameters and variables from Eq. 4: 
For Canadian provinces, the union date was the date that provinces were admitted to Canada. For other nations, the union date was the date that countries gained independence and were self-governing. Population values were obtained from the U.S. Census Bureau International Database. We provide the mean and standard deviation based on the 50 U.S. states, which were used to standardize the input and output variables in Eq. 4.
*
Observed values not within the model's 95% prediction intervals.