condition mean min max ZT0-3 11.8 11.8 11.8 ZT4-7 28.2 28.2 28.2 ZT8-11 35.45 35.45 35.45 ZT12-15 7.5 7.5 7.5 ZT16-19 6.8999999999999995 6.8999999999999995 6.8999999999999995 ZT20-23 5.9 5.9 5.9