condition mean min max ZT0-3 1.936915 1.936915 1.936915 ZT4-7 1.627965 1.627965 1.627965 ZT8-11 1.14032 1.14032 1.14032 ZT12-15 2.33399 2.33399 2.33399 ZT16-19 3.5943300000000002 3.5943300000000002 3.5943300000000002 ZT20-23 2.0957350000000003 2.0957350000000003 2.0957350000000003