condition mean min max ZT0-3 4.2 4.2 4.2 ZT4-7 4.9 4.9 4.9 ZT8-11 6.35 6.35 6.35 ZT12-15 6.15 6.15 6.15 ZT16-19 6.2 6.2 6.2 ZT20-23 4.8 4.8 4.8