condition mean min max ZT0-3 6.9 6.9 6.9 ZT4-7 8.3 8.3 8.3 ZT8-11 7.5 7.5 7.5 ZT12-15 7.5 7.5 7.5 ZT16-19 5.35 5.35 5.35 ZT20-23 7.3999999999999995 7.3999999999999995 7.3999999999999995