condition mean min max ZT0-3 9.6 9.6 9.6 ZT4-7 4.0 4.0 4.0 ZT8-11 6.1 6.1 6.1 ZT12-15 18.9 18.9 18.9 ZT16-19 9.5 9.5 9.5 ZT20-23 8.4 8.4 8.4