condition mean min max ZT0-3 3.3499999999999996 3.3499999999999996 3.3499999999999996 ZT4-7 22.9 22.9 22.9 ZT8-11 6.6499999999999995 6.6499999999999995 6.6499999999999995 ZT12-15 6.85 6.85 6.85 ZT16-19 6.800000000000001 6.800000000000001 6.800000000000001 ZT20-23 20.4 20.4 20.4