condition mean min max ZT0-3 3.619676666666667 2.7022500000000003 4.233275 ZT4-7 3.4859099999999996 3.4859099999999996 3.4859099999999996 ZT8-11 3.163935 3.163935 3.163935 ZT12-15 3.3230975000000003 3.162575 3.48362 ZT16-19 3.477225 3.477225 3.477225 ZT20-23 4.039540000000001 4.039540000000001 4.039540000000001