condition mean min max ZT0-3 3.810808333333333 2.34993 5.161485 ZT4-7 3.8560600000000003 3.8560600000000003 3.8560600000000003 ZT8-11 8.8764 8.8764 8.8764 ZT12-15 18.405975 16.42235 20.3896 ZT16-19 11.03425 11.03425 11.03425 ZT20-23 10.610675 10.610675 10.610675