condition mean min max ZT0-3 6.25 6.25 6.25 ZT4-7 7.2 7.2 7.2 ZT8-11 5.0 5.0 5.0 ZT12-15 11.75 11.75 11.75 ZT16-19 2.95 2.95 2.95 ZT20-23 4.7 4.7 4.7