condition mean min max ZT0-3 2.5460949999999998 1.86577 2.9798799999999996 ZT4-7 2.0255900000000002 2.0255900000000002 2.0255900000000002 ZT8-11 3.016475 3.016475 3.016475 ZT12-15 5.0809525 4.872625 5.28928 ZT16-19 4.949905 4.949905 4.949905 ZT20-23 5.01202 5.01202 5.01202