condition mean min max ZT0-3 6.6000000000000005 6.6000000000000005 6.6000000000000005 ZT4-7 3.1 3.1 3.1 ZT8-11 8.55 8.55 8.55 ZT12-15 4.1 4.1 4.1 ZT16-19 38.9 38.9 38.9 ZT20-23 13.85 13.85 13.85