condition mean min max ZT0-3 5.2 5.2 5.2 ZT4-7 3.5 3.5 3.5 ZT8-11 12.2 12.2 12.2 ZT12-15 4.15 4.15 4.15 ZT16-19 3.95 3.95 3.95 ZT20-23 9.1 9.1 9.1