condition mean min max ZT0-3 4.094503333333334 2.61332 5.45366 ZT4-7 1.55101 1.55101 1.55101 ZT8-11 2.2766349999999997 2.2766349999999997 2.2766349999999997 ZT12-15 3.13824 3.0562050000000003 3.220275 ZT16-19 4.119775 4.119775 4.119775 ZT20-23 6.262035 6.262035 6.262035