condition mean min max ZT0-3 6.8 6.8 6.8 ZT4-7 58.3 58.3 58.3 ZT8-11 15.899999999999999 15.899999999999999 15.899999999999999 ZT12-15 33.9 33.9 33.9 ZT16-19 18.2 18.2 18.2 ZT20-23 58.550000000000004 58.550000000000004 58.550000000000004