condition mean min max ZT0-3 9.4 9.4 9.4 ZT4-7 4.1 4.1 4.1 ZT8-11 6.5 6.5 6.5 ZT12-15 8.45 8.45 8.45 ZT16-19 10.1 10.1 10.1 ZT20-23 5.85 5.85 5.85