condition mean min max ZT0-3 7.6 7.6 7.6 ZT4-7 9.3 9.3 9.3 ZT8-11 5.55 5.55 5.55 ZT12-15 5.25 5.25 5.25 ZT16-19 8.95 8.95 8.95 ZT20-23 8.25 8.25 8.25