condition mean min max ZT0-3 18.0804 18.0804 18.0804 ZT4-7 15.866900000000001 15.866900000000001 15.866900000000001 ZT8-11 15.22305 15.22305 15.22305 ZT12-15 15.637550000000001 15.637550000000001 15.637550000000001 ZT16-19 20.2184 20.2184 20.2184 ZT20-23 18.8478 18.8478 18.8478