condition mean min max ZT0-3 4.35 4.35 4.35 ZT4-7 26.2 26.2 26.2 ZT8-11 28.5 28.5 28.5 ZT12-15 1.4 1.4 1.4 ZT16-19 15.899999999999999 15.899999999999999 15.899999999999999 ZT20-23 3.95 3.95 3.95