condition mean min max ZT0-3 2.55846 2.55846 2.55846 ZT4-7 2.02067 2.02067 2.02067 ZT8-11 3.5971149999999996 3.5971149999999996 3.5971149999999996 ZT12-15 3.9162150000000002 3.9162150000000002 3.9162150000000002 ZT16-19 5.411754999999999 5.411754999999999 5.411754999999999 ZT20-23 2.88666 2.88666 2.88666