condition mean min max ZT0-3 21.933647 21.933647 21.933647 ZT4-7 17.8653775 17.8653775 17.8653775 ZT8-11 16.651523 16.651523 16.651523 ZT12-15 14.4540845 14.4540845 14.4540845 ZT16-19 14.3332375 14.3332375 14.3332375 ZT20-23 16.1656745 16.1656745 16.1656745