condition mean min max ZT0-3 5.65 5.65 5.65 ZT4-7 4.1 4.1 4.1 ZT8-11 21.75 21.75 21.75 ZT12-15 20.799999999999997 20.799999999999997 20.799999999999997 ZT16-19 4.3 4.3 4.3 ZT20-23 17.849999999999998 17.849999999999998 17.849999999999998