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Kendall τb correlation ranks.
| Correlation | Rank |
| ±0.10a | Very weak |
| ±0.10 to 0.19 | Weak |
| ±0.20 to 0.29 | Moderate |
| ±0.30 | Strong |
aA positive sign indicates a positive relationship, and a negative sign indicates a negative relationship. A ± value means that the correlation value can either be positive or negative for each rank (eg, a 0.15 correlation would be weak, as would a –0.15 correlation).
