condition mean min max ZT0-3 6.95 6.95 6.95 ZT4-7 9.1 9.1 9.1 ZT8-11 7.4 7.4 7.4 ZT12-15 9.45 9.45 9.45 ZT16-19 7.95 7.95 7.95 ZT20-23 21.25 21.25 21.25