condition mean min max ZT0-3 18.0719 18.0719 18.0719 ZT4-7 16.2753 16.2753 16.2753 ZT8-11 17.0561 17.0561 17.0561 ZT12-15 15.93525 15.93525 15.93525 ZT16-19 17.585299999999997 17.585299999999997 17.585299999999997 ZT20-23 17.9512 17.9512 17.9512