condition mean min max ZT0-3 4.300000000000001 4.300000000000001 4.300000000000001 ZT4-7 5.2 5.2 5.2 ZT8-11 7.6499999999999995 7.6499999999999995 7.6499999999999995 ZT12-15 3.5 3.5 3.5 ZT16-19 5.5 5.5 5.5 ZT20-23 6.15 6.15 6.15