Table 6 Grey prediction accuracy test level criteria.
Vintages | Original value | Projected value | Residual | Relative error (%) | Gradation deviation |
|---|---|---|---|---|---|
2010 | 0.6225 | 0.622 | 0.000 | 0.00 | – |
2011 | 0.6390 | 0.662 | − 0.023 | 3.60 | 0.005 |
2012 | 0.6086 | 0.612 | − 0.004 | 0.59 | − 0.052 |
2013 | 0.5656 | 0.566 | 0.000 | 0.07 | − 0.018 |
2014 | 0.5104 | 0.523 | − 0.013 | 2.53 | − 0.138 |
2015 | 0.5004 | 0.484 | 0.017 | 3.32 | 0.018 |
2016 | 0.5081 | 0.469 | 0.039 | 7.74 | 0.104 |
2017 | 0.4677 | 0.451 | 0.016 | 3.52 | 0.062 |
2018 | 0.3775 | 0.382 | − 0.005 | 1.30 | − 0.094 |
2019 | 0.3088 | 0.352 | − 0.043 | 13.95 | 0.126 |
2020 | 0.2785 | 0.324 | − 0.046 | 16.53 | − 0.324 |
C = 0.1396 | P = 0.800 | ||||
