condition mean min max ZT0-3 5.556915 5.556915 5.556915 ZT4-7 3.927955 3.927955 3.927955 ZT8-11 3.0626800000000003 3.0626800000000003 3.0626800000000003 ZT12-15 4.505050000000001 4.505050000000001 4.505050000000001 ZT16-19 6.493595000000001 6.493595000000001 6.493595000000001 ZT20-23 4.72256 4.72256 4.72256