condition mean min max ZT0-3 12.05 12.05 12.05 ZT4-7 8.6 8.6 8.6 ZT8-11 6.6 6.6 6.6 ZT12-15 9.65 9.65 9.65 ZT16-19 6.95 6.95 6.95 ZT20-23 6.75 6.75 6.75