condition mean min max ZT0-3 14.1 14.1 14.1 ZT4-7 11.1 11.1 11.1 ZT8-11 7.95 7.95 7.95 ZT12-15 6.4 6.4 6.4 ZT16-19 6.35 6.35 6.35 ZT20-23 2.55 2.55 2.55