condition mean min max ZT0-3 2.7335982899999998 2.491468365 2.975728215 ZT4-7 1.622007867 1.304200212 1.939815522 ZT8-11 1.8000302195 1.741929618 1.8581308209999998 ZT12-15 5.92296750525 4.4499891795 7.395945831000001 ZT16-19 8.9848556175 8.5783475935 9.3913636415 ZT20-23 9.939750399000001 9.010865758000001 10.868635040000001