condition mean min max ZT0-3 9.9 9.9 9.9 ZT4-7 0.9 0.9 0.9 ZT8-11 5.4 5.4 5.4 ZT12-15 11.3 11.3 11.3 ZT16-19 8.25 8.25 8.25 ZT20-23 0.75 0.75 0.75