condition mean min max ZT0-3 5.55 5.55 5.55 ZT4-7 35.4 35.4 35.4 ZT8-11 12.0 12.0 12.0 ZT12-15 6.5 6.5 6.5 ZT16-19 7.55 7.55 7.55 ZT20-23 7.0 7.0 7.0