Table 3: The classification of thirteen data sets.
| Group | Date | Parameters |
| Group 1 | 4-13, 5-30 | k1 > k > 0, c < a < 0 |
| Group 2 | 6-30, 7-15, 7-31, 11-15, 11-29 | k1 > k > 0, c > a > 0a |
| Group 3 | 8-15, 9-15, 11-01 | k > 0, a > 0, c = 0 |
| Group 4 | 9-01, 9-30, 10-15 | k1 > k >0, c > a >0b |
a The difference between k1 and k is larger than 0.005; b The k1 and k difference is not bigger than 0.005.