condition mean min max ZT0-3 4.0 4.0 4.0 ZT4-7 1.3 1.3 1.3 ZT8-11 13.2 13.2 13.2 ZT12-15 8.0 8.0 8.0 ZT16-19 6.75 6.75 6.75 ZT20-23 3.55 3.55 3.55