condition mean min max ZT0-3 9.35 9.35 9.35 ZT4-7 4.1 4.1 4.1 ZT8-11 6.1 6.1 6.1 ZT12-15 4.9 4.9 4.9 ZT16-19 4.55 4.55 4.55 ZT20-23 7.85 7.85 7.85