condition mean min max ZT0-3 6.300000000000001 6.300000000000001 6.300000000000001 ZT4-7 0.6 0.6 0.6 ZT8-11 5.7 5.7 5.7 ZT12-15 9.25 9.25 9.25 ZT16-19 7.8999999999999995 7.8999999999999995 7.8999999999999995 ZT20-23 1.3 1.3 1.3