condition mean min max ZT0-3 9.25 9.25 9.25 ZT4-7 8.8 8.8 8.8 ZT8-11 8.1 8.1 8.1 ZT12-15 8.4 8.4 8.4 ZT16-19 4.25 4.25 4.25 ZT20-23 7.35 7.35 7.35