condition mean min max ZT0-3 6.800000000000001 6.800000000000001 6.800000000000001 ZT4-7 4.9 4.9 4.9 ZT8-11 4.85 4.85 4.85 ZT12-15 4.3 4.3 4.3 ZT16-19 4.8 4.8 4.8 ZT20-23 5.5 5.5 5.5