condition mean min max ZT0-3 3.3499999999999996 3.3499999999999996 3.3499999999999996 ZT4-7 2.5 2.5 2.5 ZT8-11 9.549999999999999 9.549999999999999 9.549999999999999 ZT12-15 3.0 3.0 3.0 ZT16-19 2.4 2.4 2.4 ZT20-23 3.9000000000000004 3.9000000000000004 3.9000000000000004