condition mean min max ZT0-3 4.769691268 4.258819265 5.280563271 ZT4-7 6.86454800575 5.2397365065 8.489359505 ZT8-11 9.51848111825 7.593342256500001 11.44361998 ZT12-15 12.88311205325 11.42723123 14.3389928765 ZT16-19 11.68822006225 9.9386230395 13.437817084999999 ZT20-23 19.607621815 17.25878855 21.95645508