condition mean min max ZT0-3 7.238525 7.238525 7.238525 ZT4-7 3.38773 3.38773 3.38773 ZT8-11 13.0522 13.0522 13.0522 ZT12-15 9.07401 9.07401 9.07401 ZT16-19 15.1279 15.1279 15.1279 ZT20-23 11.493400000000001 11.493400000000001 11.493400000000001