condition mean min max ZT0-3 17.9509 17.9509 17.9509 ZT4-7 1.45878 1.45878 1.45878 ZT8-11 6.511035 6.511035 6.511035 ZT12-15 9.11719 9.11719 9.11719 ZT16-19 17.160200000000003 17.160200000000003 17.160200000000003 ZT20-23 18.55135 18.55135 18.55135